During the Reformation, the advance of the Muslim religion was very much “in the news.” The advancing Turkish Ottoman Empire, which reached its height in the early to mid-sixteenth century, posed an unnerving political and military threat to European Christendom. Even though the armies of Europe turned back the Turks at the gates of Vienna in 1529, the fact that the forces of Islam had made it that far left Christian Europe “severely rattled” for decades to come. Thus, while primarily doing battle with the Roman Catholic Church, the Reformers also gave occasional attention to Islam. In addition to explaining the nature of Islam, the Reformers pondered what lessons God wanted the church to draw from the advance of “the Turks” (synonymous then with “Muslims”) upon an outwardly Christian people.
As we’ve just recognized the five-hundredth anniversary of the Reformation, we find ourselves troubled by these same questions. It seems timely to ask, how did the Reformers view Islam?
The Nature of Islam
The Reformers did not consider Islam “one of the world’s great religions” or “one of the three Abrahamic faiths.” Rather, they predominantly thought of Muhammad’s teachings as a heretical deviation from Christianity.
The word heresy comes from the Greek meaning “to pick, to choose,” and as such, a Christian heresy does not receive the Christian faith as a whole but rather selects certain elements at the expense of others. What’s left is something that has been extracted from Christianity but is no longer Christianity. Two of the most well-known heresies in church history are Arianism (a heresy that denies the eternal Trinity) and Pelagianism (a heresy that denies original sin and teaches salvation by works). The church’s struggle against heresy has been perennial.
Arising in the seventh century in a region once influenced by Christianity, Islam purports to retain the original revelation of God given in the Old and New Testaments (though Islam claims that the Bible possessed by Christianity is corrupted). It also retains the confession of monotheism and a belief in the immortality of the soul. It rejects, however, several critical elements of Christianity, chiefly the doctrines of the Trinity and of the incarnation. In other words, it picks and chooses from among Christian beliefs, as heresies do.
Accordingly, writing less than a century after the founding of Islam, the great Christian theologian (and native of Syria) John of Damascus categorized Islam as one among many heresies. In his book Concerning Heresy, John gave his most extended attention to Islam, writing of Muhammad that “this man, after having chanced upon the Old and New Testament and likewise, it seems, having conversed with an Arian (heretical) monk, devised his own heresy.” John then highlights numerous points of concern, including that (a) the revelation Muhammad claimed to receive was received without witnesses; (b) Muslims allow men to take more than one wife (up to four); and (c) they allow men to divorce their wives easily.
In the twelfth century, Peter the Venerable (1092–1156) devoted himself to studying Islam in its original sources, even commissioning a complete translation of Islam’s sacred writings into elegant Latin. Peter then wrote about Islam and maintained that it was a Christian heresy, one that went so far afield as to approach paganism.
As we come to the Reformers in the sixteenth century, we encounter Heinrich Bullinger (1504–1575), Huldrych Zwingli’s successor in Zurich, who studied and wrote more extensively about Islam than any other Reformer. Bullinger also viewed Islam as a heresy composed of several heresies—the denial of the Trinity, the denial of Christ’s atoning work as mediator, and the affirmation that human beings can be saved by works, which he connected to the heresy of Pelagianism. Bullinger understood the claim that Muhammad was God’s prophet as fulfilling what Jesus taught in John 5:43: “I have come in my Father’s name, and you do not receive me. If another comes in his own name, you will receive him.”
And what of our celebrated forebear John Calvin? In his commentary on 2 Thessalonians, written in 1550, Calvin briefly references “the Turks” when commenting on 2 Thessalonians 2:3. Describing Islam as a “defection” that has “spread more widely,” Calvin understands Muhammad’s work as that of “turn[ing] his followers, the Turks, from Christ.” Consequently, Calvin says that Islam “in its violence tore away about half of the Church.”
In describing its effects, Calvin also diagnoses the root theological error of Islam. Ever the champion of sola Scriptura, Calvin lays the blame at the feet of their faulty doctrine of Scripture. For though they ostensibly hold to revelation given in the Old and New Testaments, Muslims recognize additional revelation (in much the same way that Mormons do today), and thus they “keep not themselves fast enclosed within the bounds of Holy Scripture!”
In summary, the Reformers broadly viewed Islam as a Christian heresy that, having selected some elements of Christianity and rejected others, took root and spread in areas where true Christianity had been eclipsed by substantial degeneration in faith and life. What lessons, then, did the Reformers draw for the church in their day?