Theopedia

Islam

Islam is a monotheistic religion that originated with the prophet Muhammad in seventh-century Arabia. The word islam means “surrender”: believers submit to the will of Allah (God).1 Muslims hold Muhammad to be the last in a line of prophets sent by God, including Adam, Noah, Abraham, Moses, and Jesus, and regard the Qur’an, which Muhammad began receiving in 610, as God’s final, definitive revelation, superseding the Torah and the Gospel.1 With roughly two billion adherents, Islam is the world’s second-largest religion after Christianity.2

Historical Origin

Muhammad was born around 570 in Mecca, in the Arabian Peninsula, into a family of the ruling Quraysh tribe, and was orphaned by about age six.3 He worked as a merchant and, in his twenties, married Khadijah, a wealthy widow, with whom he had several children.3 According to Islamic tradition, Muhammad received his first revelation from the angel Gabriel in 610, and by about 613 he had begun preaching publicly in Mecca, urging the wealthy to give to the poor and denouncing the idols worshiped at the city’s shrines.3 Opposition from Mecca’s ruling families eventually forced Muhammad and his followers to migrate to Medina in 622, a journey known as the Hijra that marks the beginning of the Islamic calendar.3 Muhammad died in Medina in 632, by which time his followers controlled much of the Arabian Peninsula.3

Core Beliefs

Islam’s central confession, the shahada, states that “there is no god but God; Muhammad is the messenger of God.”4 Reciting the shahada with sincere belief is the sole requirement for becoming a Muslim, and it expresses both Islam’s uncompromising monotheism (tawhid) and its recognition of Muhammad’s prophetic authority.4 Alongside the shahada, Islam obligates its adherents to four further practices, together known as the Five Pillars: salat, ritual prayer performed five times daily facing Mecca; zakat, an obligatory almsgiving calculated as a fixed portion of a Muslim’s wealth for the relief of the poor; sawm, fasting from food, drink, and other activities from dawn to sunset during the month of Ramadan; and hajj, a pilgrimage to Mecca that every Muslim who is physically and financially able must make at least once in a lifetime.4

Muslims regard the Qur’an as God’s own speech, delivered to Muhammad in Arabic through the angel Gabriel.1 Islam also affirms Jesus (Isa) as one of God’s major prophets, born of the virgin Mary, but denies that he is the Son of God or in any way divine.5 The Qur’an further teaches that Jesus was not killed or crucified, but that it was made to appear so to those present (Qur’an 4:157).6

Confessional Witness

Neither the 1689 Second London Baptist Confession nor its Westminster and Savoy relatives address Islam by name; the confessions were framed against controversies within and immediately surrounding the Western church, not against a later, separate religion. Their bearing on Islam’s central claim is instead structural: the confession states that “the whole counsel of God concerning all things necessary for his own glory, man’s salvation, faith and life, is either expressly set down or necessarily contained in the Holy Scripture: unto which nothing at any time is to be added, whether by new revelation of the Spirit, or traditions of men.”7 On this confessional principle, any later writing claiming to supersede or complete the Bible, whatever its own internal claims to revelation, falls under the same judgment the confession applies to any purported addition to Scripture.

Objections and Responses

Muhammad’s own claim to prophetic authority is sufficient warrant for it. Petrus van Mastricht, writing a systematic Reformed refutation of Islam’s claims in the late seventeenth century, organized his response around three points: that the Christian Scriptures had not been corrupted, as Muslim polemicists commonly alleged; that Muhammad was not a true prophet; and that the Qur’an is not a divinely inspired writing.8 Against the claim to prophetic authority in particular, Mastricht argued that Muhammad’s own testimony cannot certify itself, and that he showed none of the marks by which Scripture identifies a true prophet: “What mystery did he reveal? What prophecies did he utter? What miracles did he perform?”9 Mastricht further argued that Muhammad’s teaching openly contradicted Moses and the biblical prophets, and pointed to Muhammad’s own polygamous marriages as evidence against the moral character expected of a prophet.9

The Qur’an is itself divine revelation, delivered through the angel Gabriel. Mastricht answered that Muslims assert this claim without proving it, and that the burden of proof rests on whoever makes the positive claim.10 He also pointed to what he took as an inconsistency in the Qur’an’s own account of its origin, noting that it describes itself in one place as delivered to Muhammad directly by God and in another as sent through the angel Gabriel, and in one place as composed by God and in another as composed by men.9

Muslims and Christians both honor Jesus, so the two faiths are not far apart on this point. The Qur’an’s own regard for Jesus does not extend to the claim actually at issue between the two faiths. Mastricht placed the Qur’an’s denial that Jesus is the Son of God within a wider survey of historic denials of Christ’s eternal sonship, alongside Cerinthus, Arius, Paul of Samosata, and the Socinians, observing plainly that “Muhammad in his Qur’an… denies that he is the Son of God.”5 The Qur’an also denies that Jesus was crucified (Qur’an 4:157), at odds with the event Christian confession holds central to the atonement.6

Related Doctrines

Further Reading

  • A Common Word Between Us and You, a document by Muslim scholars declaring common ground between Islam and Christianity.
  • Norman L. Geisler and Abdul Saleeb, Answering Islam: The Crescent in Light of the Cross, 2nd ed. (Grand Rapids: Baker, 2002).

References

  1. Encyclopaedia Britannica, s.v. “Islam,” accessed September 2026. ↩ ↩2 ↩3

  2. Pew Research Center, “Countries with the Most Muslims & Global Muslim Population Change, 2010-2020” (June 9, 2025). ↩

  3. Encyclopaedia Britannica, s.v. “Muhammad,” accessed September 2026. ↩ ↩2 ↩3 ↩4 ↩5

  4. Encyclopaedia Britannica, s.v. “Pillars of Islam,” accessed September 2026. ↩ ↩2 ↩3

  5. Petrus van Mastricht, Theoretical-Practical Theology, vol. 2, Faith in the Triune God, ed. Joel R. Beeke, trans. Todd M. Rester (Grand Rapids: Reformation Heritage Books, 2019), chap. 26, “God the Son,” 592-593. ↩ ↩2

  6. Qur’an 4:157. ↩ ↩2

  7. The Second London Baptist Confession of Faith (1689), chap. 1, “Of the Holy Scriptures,” para. 6. ↩

  8. Petrus van Mastricht, Theoretical-Practical Theology, vol. 1, Prolegomena, trans. Todd M. Rester, ed. Joel R. Beeke, from the 1699 Latin edition of Theoretico-practica theologia (Grand Rapids: Reformation Heritage Books, 2018), chap. 2, “Holy Scripture,” 241-242. ↩

  9. Mastricht, Theoretical-Practical Theology, vol. 1, 243. ↩ ↩2 ↩3

  10. Mastricht, Theoretical-Practical Theology, vol. 1, 244. ↩