Protestantism is one of the four major divisions within Christianity, together with the Eastern Orthodox Church, the Catholic Church, and the Anglican Church traditions. The term is most closely tied to those groups that separated from the Roman Catholic Church in the 16th century Protestant Reformation.
The doctrines of the various Protestant denominations vary, but nearly unanimous doctrines include justification by grace through faith and not through works, the priesthood of all believers, and the Bible as the ultimate authority in matters of faith and order. In the early 21st century there were nearly 350 million Protestants in the world.
The followers of Luther established the evangelical churches of Germany and Scandinavia. Reformed churches in Switzerland were established by John Calvin and more radical reformers such as Huldrych Zwingli, while John Knox established an influential Presbyterian communion as the national church in Scotland.
The term Protestant is derived from the Latin protestari  meaning publicly declare/protest which refers to the letter of protestation by Lutheran princes against the decision of the Diet of Speyer in 1529, which reaffirmed the edict of the Diet of Worms in 1521, banning Luther's documents. Since that time, the term Protestantism has been used in many different senses, often as a general term merely to signify people who believe in Christ who exist outside of the Catholic or Orthodox Churches.
- Sola scriptura maintains that the Bible (rather than church tradition or ecclesiastical interpretations of the Bible) is the final source of authority for all Christians.
- Sola fide holds that salvation comes by faith alone in Jesus as the Christ, rather than through good works.
Protestant churches generally reject the Catholic and Orthodox doctrines of apostolic succession and the sacramental ministry of the clergy. Exceptions are found mostly in countries, such as in the southern parts of Europe, that came under non-Catholic influences long before the Reformation.
Luther's theses debated and criticized the Church and the Pope, but concentrated upon the selling of indulgences and the doctrines of purgatory, particular judgment, Mariology (devotion to Mary, Jesus’ Mother), the intercession of and devotion to the saints, most of the sacraments, the mandatory clerical celibacy including monasticism, and the authority of the Pope.
Protestant ministers and church leaders have somewhat different roles and authority in their communities than do Catholic, Anglican and Orthodox priests and bishops.
Protestantism has both conservative and liberal theological strands within it. Protestant styles of public worship tend to be simpler and less elaborate than those of Roman Catholics, Anglicans, and Eastern Christians, sometimes radically so, though there are exceptions to this tendency.
Dissension in the ranks of Protestantism
The reformers soon disagreed among themselves and divided their movement according to doctrinal differences—first between Luther and Zwingli, later between Luther and John Calvin—consequently resulting in the establishment of different and rival Protestant denominations such as the Lutheran, Reformed, Anabaptist, and others.
The three fundamental principles of traditional Protestantism are the following:
- Authority of Scripture
- The belief in the Bible as the primary source of faith. The early churches of the Reformation believed in a critical, yet serious, reading of Scripture and holding the Bible as a source of authority higher than that of Church Tradition. The many abuses that had occured in the Western Church prior to the Protestant Reformation led the Reformers to reject much of the Tradition of the Western Church, though some would maintain Tradition has been maintained and reorganized in the liturgy and in the confessions of the Protestant Churches of the Reformation. In the early 20th century there developed a less critical reading of the Bible in the United States that has led to a "fundamentalist" reading of Scripture. Christian Fundamentalists read the Bible as the "inerrant, infallible" Word of God, much like fundamentalist Muslims would read the Qu'ran.
- Justification by Faith Alone
- The subjective principle of the Reformation is justification by faith alone, or, rather, by free grace through faith operative in good works. It has reference to the personal appropriation of the Christian salvation, and aims to give all glory to Christ, by declaring that the sinner is justified before God (i.e., is acquitted of guilt, and declared righteous) solely on the ground of the all-sufficient merits of Christ as apprehended by a living faith, in opposition to the theory—then prevalent, and substantially sanctioned by "the Council of Trent—which makes faith and good works co-ordinate sources of justification, laying the chief stress upon works. Protestantism does not depreciate good works; but it denies their value as sources or conditions of justification, and insists on them as the necessary fruits of faith, and evidence of justification."
- Universal Priesthood of Believers
- The universal priesthood of believers implies the right and duty of the Christian laity not only to read the Bible in the vernacular, but also to take part in the government and all the public affairs of the Church. It is opposed to the hierarchical system which puts the essence and authority of the Church in an exclusive priesthood, and makes ordained priests the necessary mediators between God and the people.
The term Protestant is often used loosely to denote all non-Roman Catholic varieties of Western Christianity, rather than to refer to those churches adhering to the principles described below. Trinitarian Protestant denominations are divided according to the position taken on Baptism:
- "Mainline Protestants," a North American phrase, are Christians who trace their tradition's lineage to Lutheranism, Calvinism, and even Anglicanism. These groups are often considered to be part of the Magisterial Reformation and traditionally have adhered to the central doctrines and principles of the Reformation. Lutheranism, Calvinism, and a Zwinglian theology are typically mainline, and as denominations, "mainline" is typically seen as referring to Methodists, Presbyterians, Anglican/Episcopalian, and Lutherans, all large denominations with significant liberal and conservative wings.
- Anabaptists were so named from the fact that they re-baptised converts. According to the Edinburg Cyclopedia this name dates as far back as Tertullian, who was born just fifty years after the Apostle John; by about 1600 they were referred to simply as Baptists. Many Baptists do not claim to be Protestant, as this claims a heritage from the Protestant Reformation which came through the Roman Catholic Church, of which the Anabaptists were never a part. Today, denominations such as the Brethren, Mennonites, Hutterites, and Amish eschew infant baptism and have historically been Peace churches. Typically, independent Pentecostal and Charismatic denominations, and the house church movement belong in this category too.
- Certain Protestant denominations including Baptists, the Quakers and the Shakers, do not practise Baptism sacramentally. These denominations view baptism as part of a process on ongoing renewal. Antecedents of these beliefs may be found in Strigolniki theology. Normatively, the Salvation Army does not practise Baptism.
There are many independent, non-aligned or non-denominational Trinitarian congregations that may take any one of these or no particular position on Baptism.
Other groups rejecting Protestant label
Some religious movements, such as Restorationists, Nontrinitarian movements, and the New Religious Movements which share certain characteristics of Protestant churches, are sometimes termed 'Protestant' by some outsiders even though neither mainstream Trinitarian Christians, nor the groups themselves, would consider the designation appropriate.
Protestants refer to specific Protestant groupings of churches that share in common foundational doctrines and the name of their groups as "denominations". They are differently named parts of the whole "church"; Protestants reject the Catholic doctrine that it is the one true church. Some Protestant denominations are less accepting of other denominations, and the basic orthodoxy of some is questioned by most of the others. Individual denominations also have formed over very subtle theological differences. Other denominations are simply regional or ethnic expressions of the same beliefs. Because the five solas are the main tenets of the Protestant faith, Non-denominational groups and organizations are also considered Protestant.
Various ecumenical movements have attempted cooperation or reorganization of the various divided Protestant denominations, according to various models of union, but divisions continue to outpace unions, as there is no overarching authority to which any of the sects owe allegiance, which can authoritatively define the faith. Most denominations share common beliefs in the major aspects of the Christian faith, while differing in many secondary doctrines, although what is major and what is secondary is a matter of idiosyncratic belief. According to World Christian Encyclopedia, there are "over 33,000 denominations in 238 countries," having increased in number from 8,196 in 1970. Every year there is a net increase of around 270 to 300 denominations.
There are about 800 million Protestants worldwide, among approximately 2.2 billion Christians. These include 170 million in North America, 160 million in Africa, 120 million in Europe, 70 million in Latin America, 60 million in Asia, and 10 million in Oceania.
Protestants can be differentiated according to how they have been influenced by important movements since the magisterial Reformation and the Puritan Reformation in England. Some of these movements have a common lineage, sometimes directly spawning later movements in the same groups. Only general families are listed here (due to the above-stated multitude of denominations); some of these groups do not consider themselves as part of the Protestant movement, but are generally viewed as such by the public at large:
- Methodist / Wesleyan
- Plymouth Brethren
- Religious Society of Friends (Quaker)
- Restoration movement
- Seventh-day Adventist
Theological tenets of the reformation
The Five Solas are five Latin phrases (or slogans) that emerged during the Protestant Reformation and summarize the Reformers' basic differences in theological beliefs in opposition to the teaching of the Catholic Church of the day. The Latin word sola means "alone", "only", or "single".
The use of the phrases as summaries of teaching emerged over time during the reformation, based on the overarching principle of sola scriptura (by scripture alone). This idea contains the four main doctrines on the Bible: that its teaching is needed for salvation (necessity); that all the doctrine necessary for salvation comes from the Bible alone (sufficiency); that everything taught in the Bible is correct (inerrancy); and that, by the Holy Spirit overcoming sin, believers may read and understand truth from the Bible itself, though understanding is difficult, so the means used to guide individual believers to the true teaching is often mutual discussion within the church (clarity). The necessity and inerrancy were well-established ideas, garnering little criticism, though they later came under debate from outside during the Enlightenment. The most contentious idea at the time though was the notion that anyone could simply pick up the Bible and learn enough to gain salvation. Though the reformers were concerned with ecclesiology (the doctrine of how the church as a body works), they had a different understanding of the process in which truths in scripture were applied to life of believers, compared to the Catholics' idea that certain people within the church, or ideas that were old enough, had a special status in giving understanding of the text.
The second main principle, sola fide (by faith alone), states that faith in Christ is sufficient alone for eternal salvation. Though argued from scripture, and hence logically consequent to sola scriptura, this is the guiding principle of the work of Luther and the later reformers. As sola scriptura placed the bible as the only source of teaching, sola fide epitomises the main thrust of the teaching the reformers wanted to get back to, namely the direct, close, personal connection between Christ and the believer, hence the reformers' contention that their work was Christocentric.
The other solas, as statements, emerged later, but the thinking they represent was also part of the early reformation.
- Solus Christus: Christ alone.
- The Protestants characterize the dogma concerning the Pope as Christ's representative head of the Church on earth, the concept of works made meritorious by Christ, and the Catholic idea of a treasury of the merits of Christ and his saints, as a denial that Christ is the only mediator between God and man. Catholics, on the other hand, maintained the traditional understanding of Judaism on these questions, and appealed to the universal consensus of Christian tradition.
- Sola Gratia: Grace Alone.
- Protestants perceived Roman Catholic salvation to be dependent upon the grace of God and the merits of one's own works. The Reformers posited that salvation is a gift of God (i.e., God's act of free grace), dispensed by the Holy Spirit owing to the redemptive work of Jesus Christ alone. Consequently, they argued that a sinner is not accepted by God on account of the change wrought in the believer by God's grace, and that the believer is accepted without regard for the merit of his works—for no one deserves salvation.
- Soli Deo Gloria: Glory to God Alone
- All glory is due to God alone, since salvation is accomplished solely through his will and action—not only the gift of the all-sufficient atonement of Jesus on the cross but also the gift of faith in that atonement, created in the heart of the believer by the Holy Spirit. The reformers believed that human beings—even saints canonized by the Catholic Church, the popes, and the ecclesiastical hierarchy—are not worthy of the glory
Christ's presence in the Lord's Supper
The Protestant movement began to coalesce into several distinct branches in the mid-to-late sixteenth century. One of the central points of divergence was controversy over the Lord's Supper. Early Protestants rejected the Roman Catholic dogma of transubstantiation, which teaches that the bread and wine used in the sacrificial rite of the Mass lose their natural substance by being transformed into the Body, Blood, Soul, and Divinity of Christ. They disagreed with one another concerning the presence of Christ and his body and blood in Holy Communion.
- Lutherans hold that within the Lord's Supper the consecrated elements of bread and wine are the true body and blood of Christ "in, with, and under the form" of bread and wine for all those who eat and drink it, a doctrine that the Formula of Concord calls the Sacramental union. God earnestly offers to all who receive the sacrament forgiveness of sins and eternal salvation.
- The Reformed closest to Calvin emphasize the real presence, or sacramental presence, of Christ, saying that the sacrament is a means of saving grace through which only the elect believer actually partakes of Christ, but merely WITH the Bread & Wine rather than in the Elements. Calvinists deny the Lutheran assertion that all communicants, both believers and unbelievers, orally receive Christ's body and blood in the elements of the sacrament, but instead affirm that Christ is united to the believer through faith—toward which the supper is an outward and visible aid, this is often referred to as dynamic presence. Why this aid is necessary in addition to faith differs according to the believer. Some Protestants (such as the Salvation Army) do not believe it is necessary at all.
- A Protestant holding a popular simplification of the Zwinglian view, without concern for theological intricacies as hinted at above, may see the Lord's Supper merely as a symbol of the shared faith of the participants, a commemoration of the facts of the crucifixion, and a reminder of their standing together as the Body of Christ (a view referred to somewhat derisively as memorialism).
The official Roman Catholic view on the matter is that Protestant communities cannot be considered "churches", but rather that they are mere ecclesial communities or "specific faith believing communities" because their sacraments, doctrines, lack of authentic apostolic succession do not follow Catholic Doctrine.
Contrary to how the Protestant reformers were often characterized, the concept of a catholic or universal Church was not brushed aside during the Protestant Reformation. On the contrary, the visible unity of the Catholic Church was an important and essential doctrine of the Reformation. The Magisterial Reformers, such as Martin Luther, John Calvin, and Ulrich Zwingli, believed that they were "reforming" the Catholic Church, which they viewed as having become corrupted. Each of them took very seriously the charges of schism and innovation, denying these charges and maintaining that it was the Catholic Church that had left them. In order to justify their departure from the Catholic Church, Protestants often posited a new argument, saying that there was no real visible Church with divine authority, only a "spiritual", "invisible", and "hidden" church.
Wherever the Magisterial Reformation, which received support from the ruling authorities, took place, the result was a reformed national Protestant church envisioned to be a part of the whole "invisible church", but disagreeing, in certain important points of doctrine and doctrine-linked practice, with what had until then been considered the normative reference point on such matters, namely the Papacy and central authority of the Catholic Church. The Reformed churches thus believed in some form of Catholicity, founded on their doctrines of the five solas and a visible ecclesiastical organization based on the 14th and 15th century Conciliar movement, rejecting the Papacy and Papal Infallibility in favor of Ecumenical councils, but rejecting the latest ecumenical council, the Council of Trent. Religious unity therefore became not one of doctrine and identity, but one of invisible character, wherein the unity was one of faith in Jesus Christ, not common identity, doctrine, belief, and collaborative action.
Today there is a growing movement of Protestants, especially of the Reformed tradition, that reject the designation "Protestant" because of its negative "anti-catholic" connotations, preferring the designation "Reformed", "Evangelical" or even "Reformed Catholic" expressive of what they call a "Reformed Catholicity" and defending their arguments from the traditional Protestant Confessions.
Unlike mainstream Evangelical (Lutheran), Reformed (Zwinglian and Calvinist) Protestant movements, the Radical Reformation, which had no state sponsorship, generally abandoned the idea of the "Church Visible" as distinct from the "Church Invisible". It was a rational extension of the State-approved Protestant dissent, which took the value of independence from constituted authority a step further, arguing the same for the civic realm.
Protestant ecclesial leaders such as Hubmaier and Hofmann preached the invalidity of infant baptism, advocating baptism as following conversion, called "believer's baptism", instead.
In the view of many associated with the Radical Reformation, the Magisterial Reformation had not gone far enough, with radical reformer, Andreas von Bodenstein Karlstadt, for example, referring to the Lutheran theologians at Wittenberg as the "new papists". A more political side of the Radical Reformation can be seen in the thought and practice of Hans Hut, although typically Anabaptism has been associated with pacifism.
Early Anabaptists were severely persecuted by both Calvinist and Catholic civil authorities.
Movements within Protestantism
Pietism and Methodism
The German Pietist movement, together with the influence of the Puritan Reformation in England in the seventeenth century, were important influences upon John Wesley and Methodism, as well as new groups such as the Religious Society of Friends ("Quakers") and the Moravian Brethren from Herrnhut, Saxony, Germany.
The practice of a spiritual life, typically combined with social engagement, predominates in classical Pietism, which was a protest against the doctrine-centeredness Protestant Orthodoxy of the times, in favor of depth of religious experience. Many of the more conservative Methodists went on to form the Holiness movement, which emphasized a rigorous experience of holiness in practical, daily life.
Beginning at the end of eighteenth century, several international revivals of Pietism (such as the Great Awakening and the Second Great Awakening) took place across denominational lines, largely in the English-speaking world. Their teachings and successor groupings are referred to generally as the Evangelical movement. The chief emphases of this movement were individual conversion, personal piety and Bible study, public morality often including Temperance and Abolitionism, de-emphasis of formalism in worship and in doctrine, a broadened role for laity (including women) in worship, evangelism and teaching, and cooperation in evangelism across denominational lines.
Adventism, as a movement, began in the United States in middle nineteenth century. The Adventist family of churches are regarded today as conservative Protestants and considered as being the opposition to Sunderianism.
Modernism and Liberalism
Modernism and Liberalism do not constitute rigorous and well-defined schools of theology, but are rather an inclination by some writers and teachers to integrate Christian thought into the spirit of the Age of Enlightenment. New understandings of history and the natural sciences of the day led directly to new approaches to theology.
Pentecostalism, as a movement, began in the United States early in the twentieth century, starting especially within the Holiness movement. Seeking a return to the operation of New Testament gifts of the Holy Spirit, speaking in tongues as evidence of the "baptism of the Holy Ghost" or to make the unbeliever believe became the leading feature. Divine healing and miracles were also emphasized. Pentecostalism swept through much of the Holiness movement, and eventually spawned hundreds of new denominations in the United States. A later "charismatic" movement also stressed the gifts of the Spirit, but often operated within existing denominations, rather than by coming out of them.
In reaction to liberal Bible critique, fundamentalism arose in the twentieth century, primarily in the United States, among those denominations most affected by Evangelicalism. Fundamentalism placed primary emphasis on the authority and sufficiency of the Bible, and typically advised separation from error and cultural conservatism as an important aspect of the Christian life.
A non-fundamentalist rejection of liberal Christianity, associated primarily with Karl Barth, neo-orthodoxy sought to counter-act the tendency of liberal theology to make theological accommodations to modern scientific perspectives. Sometimes called "Crisis theology", according to the influence of philosophical existentialism on some important segments of the movement; also, somewhat confusingly, sometimes called neo-evangelicalism.
Evangelicalism is a movement from the middle of the twentieth century, that reacted to perceived excesses of Fundamentalism, adding to concern for biblical authority, an emphasis on liberal arts, cooperation among churches, Christian Apologetics, and non-denominational evangelization.
Paleo-orthodoxy is a movement similar in some respects to Neo-evangelicalism but emphasising the ancient Christian consensus of the undivided Church of the first millennium AD, including in particular the early Creeds and councils of the Church as a means of properly understanding the Scriptures. This movement is cross-denominational and the theological giant of the movement is United Methodist theologian Thomas Oden.
The ecumenical movement has had an influence on mainline churches, beginning at least in 1910 with the Edinburgh Missionary Conference. Its origins lay in the recognition of the need for cooperation on the mission field in Africa, Asia and Oceania. Since 1948, the World Council of Churches has been influential, but ineffective in creating a united Church. There are also ecumenical bodies at regional, national and local levels across the globe; but schisms still far outnumber unifications. One, but not the only expression of the ecumenical movement, has been the move to form united churches, such as the Church of South India, the Church of North India, The US-based United Church of Christ, The United Church of Canada, Uniting Church in Australia and the United Church of Christ in the Philippines which have rapidly declining memberships. There has been a strong engagement of Orthodox churches in the ecumenical movement, though the reaction of individual Orthodox theologians has ranged from tentative approval of the aim of Christian unity to outright condemnation of the perceived effect of watering down Orthodox doctrine.
A Protestant baptism is held to be valid in a Catholic church because it is a sacrament borrowed from the Catholic Church and derives its efficacy from Christ. However, Protestant ministers are not recognized as valid Church leaders, due to their lack of apostolic succession and their disunity from the Catholic Church. Therefore, laymen who convert are not re-baptized, although Protestant ministers who convert are ordained to the Catholic priesthood(cf Apostolicae Curae).
In 1999, the representatives of Lutheran World Federation and Catholic Church signed The Joint Declaration on the Doctrine of Justification, apparently resolving the conflict over the nature of Justification which was at the root of the Protestant Reformation, although some conservative Lutherans did not agree to this resolution. This is understandable, since there is no compelling authority within them. On July 18, 2006 Delegates to the World Methodist Conference voted unanimously to adopt the Joint Declaration.  
Founders: the first Protestant major reformers and theologians
- Twelfth century
- Peter Waldo, French reformer, founder of the earliest Protestant church, the Waldensians
- Fourteenth century
- John Wycliffe, English reformer, the "Morning Star of the Reformation".
- Fifteenth century
- Jan Hus, Catholic Priest and Professor, father of an early Protestant church (Moravianism), Czech reformist/dissident; burned to death in Constance, Holy Roman Empire in 1415 by Roman Catholic Church authorities for unrepentant and persistent heresy. After the devastation of the Hussite Wars some of his followers founded the Unitas Fratrum in 1457, "Unity of Brethren", which was renewed under the leadership of Count Zinzendorf in Herrnhut, Saxony in 1722 after its almost total destruction in the 30 Years War and Counter Reformation. Today it is usually referred to in English as the Moravian Church, in German the Herrnhuter Brüdergemeine.
- Sixteenth century
- Jacobus Arminius, Dutch theologian, founder of school of thought known as Arminianism.
- Heinrich Bullinger, successor of Zwingli, leading reformed theologian.
- John Calvin, French theologian, Reformer and resident of Geneva, Switzerland, he founded the school of theology known as Calvinism.
- Balthasar Hubmaier, influential Anabaptist theologian, author of numerous works during his five years of ministry, tortured at Zwingli's behest, and executed in Vienna.
- John Knox, Scottish Calvinist reformer.
- Martin Luther, church reformer, Father of Protestantism, theological works guided those now known as Lutherans.
- Philipp Melanchthon, early Lutheran leader.
- Menno Simons, founder of Mennonitism.
- John Smyth, early Baptist leader.
- Huldrych Zwingli, founder of Swiss reformed tradition.
- "Protestantism." Britannica Concise Encyclopedia. Encyclopædia Britannica, Inc., 2006.
- Concise Oxford English Dictionary, 11th edition Article 52364.(http://www.diclib.com/)
- O'Gorman, Robert T. and Faulkner, Mary. The Complete Idiot's Guide to Understanding Catholicism. 2003, page 317.
- Wilhelm, Joseph. "Apostolic Succession." The Catholic Encyclopedia. Vol. 1. New York: Robert Appleton Company, 1907. Web: 4 Dec. 2009
- Johann Jakob Herzog, Philip Schaff, Albert. The New Schaff-Herzog Encyclopedia of Religious Knowledge. 1911, page 419. http://books.google.com/books?id=AmYAAAAAMAAJ&pg=PA419
- World Christian Encyclopedia (2nd edition). David Barrett, George Kurian and Todd Johnson. New York: Oxford University Press, 2001
- Jay Diamond, Larry. Plattner, Marc F. and Costopoulos, Philip J. World Religions and Democracy. 2005, page 119.( also in PDF file, p49), saying "Not only do Protestants presently constitute 13 percent of the world's population—about 800 million people—but since 1900 Protestantism has spread rapidly in Africa, Asia, and Latin America."
- "between 1,250 and 1,750 million adherents, depending on the criteria employed": McGrath, Alister E. Christianity: An Introduction. 2006, page xv1.
- "2.1 thousand million Christians": Hinnells, John R. The Routledge Companion to the Study of Religion. 2005, page 441.
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- 1 Cor. 10:16, 11:20, 27, Engelder, T.E.W., Popular Symbolics. St. Louis: Concordia Publishing House, 1934. p. 95, Part XXIV. "The Lord's Supper", paragraph 131.
- The Solid Declaration of the Formula of Concord, Article 8, The Holy Supper
- Graebner, Augustus Lawrence (1910). Outlines Of Doctrinal Theology. Saint Louis, MO: Concordia Publishing House. p. 162. http://www.ctsfw.edu/etext/graebneral/soteriology.txt. ,
- Graebner, Augustus Lawrence (1910). Outlines Of Doctrinal Theology. Saint Louis, MO: Concordia Publishing House. p. 163. http://www.ctsfw.edu/etext/graebneral/soteriology.txt. ,
- Luther's Small Catechism, Part IV, The Sacrament of the Altar, "What is the benefit of such eating and drinking? That is shown us in these words: Given, and shed for you, for the remission of sins; namely, that in the Sacrament forgiveness of sins, life, and salvation are given us through these words. For where there is forgiveness of sins, there is also life and salvation." Graebner, Augustus Lawrence (1910). Outlines Of Doctrinal Theology. Saint Louis, MO: Concordia Publishing House. p. 163. http://www.ctsfw.edu/etext/graebneral/soteriology.txt.
- Responses to Some Questions Regarding Certain Aspects of the Doctrine on the Church, June 29, 2007, Congregation for the Doctrine of the Faith]].
- The Protestant Reformers formed a new theological opinion, that the visible Catholic Church is "catholic" (lower-case "c") rather than "Catholic" (upper-case "c"). Accordingly, there is not an indefinite number of Parochial, or Congregational, or National churches, constituting, as it were, so many ecclesiastical individualities, but one great spiritual republic of which these various organizations form a part, although they each have very different opinions. The visible church is not a genus, so to speak, with so many species under it. It is thus you may think of the State, but the visible church is a totum integrale, it is an empire, with an ethereal emperor, rather than a visible one. The churches of the various nationalities constitute the provinces of this empire; and though they are so far independent of each other, yet they are so one, that membership in one is membership in all, and separation from one is separation from all.... This conception of the church, of which, in at least some aspects, we have practically so much lost sight, had a firm hold of the Scottish theologians of the seventeenth century. Dr. James Walker in The Theology of Theologians of Scotland. (Edinburgh: Rpt. Knox Press, 1982) Lecture iv. pp.95-6.
- The Canadian Reformed Magazine, 18 (September 20–27, October 4–11, 18, November 1, 8, 1969) http://spindleworks.com/library/faber/008_theca.htm
- The Magisterial Reformation.
- "Adventist and Sabbatarian (Hebraic) Churches" section (p. 256–276) in Frank S. Mead, Samuel S. Hill and Craig D. Atwood, Handbook of Denominations in the United States, 12th edn. Nashville: Abingdon Press
- Challenges to Authority: The Renaissance in Europe: A Cultural Enquiry, Volume 3, by Peter Elmer, page 25.
- "What ELCA Lutherans Believe." Evangelical Lutheran Church in America. 26 July 2008 .
- Catholic websites on sola scriptura
- "Protestantism" from the 1917 Catholic Encyclopedia
- "Why Only Catholicism Can Make Protestantism Work" by Mark Brumley