Islam

At a glance

Islam is the religion founded in seventh-century Arabia through Muhammad’s preaching. Muslims confess absolute monotheism (tawhid), accept a line of prophets culminating in Muhammad, and treat the Qur’an as God’s speech in Arabic.

Jesus (‘Isa) is honored as a prophet and Messiah in the Qur’anic sense, not as eternal Son. That vocabulary, and the timeline of Muhammad’s preaching, is what a conversation about the Trinity, the Incarnation, or the Cross has to start from.

Origin and timeline

Islam arose in the Hijaz of Arabia. Around 610, Muhammad (c. 570–632) of Mecca reported revelations he attributed to God through the angel Gabriel. The early Meccan years (c. 610–622) met resistance. In 622 he and his companions migrated to Yathrib (Medina)—the Hijra, year one of the Islamic calendar. From Medina the community grew by preaching, alliance, and conflict; Mecca was taken in 630. Muhammad died in 632.

The first four caliphs (the Rashidun, 632–661)—Abu Bakr, Umar, Uthman, and Ali—expanded Islamic rule across the Near East, Egypt, and Persia. The Umayyad (661–750) and Abbasid (750–1258) caliphates shaped classical Islamic civilization. The Ottoman Empire later became the major Sunni power into the modern era. Today roughly 85–90% of Muslims are Sunni; most of the remainder are Shi‘a, with smaller communities (Ibadi, Ahmadiyya, and others).

• c. 570 — Muhammad born in Mecca
• c. 610 — First revelations (traditional dating)
• 622 — Hijra to Medina; Islamic calendar begins
• 630 — Mecca comes under Muslim control
• 632 — Death of Muhammad; Abu Bakr becomes first caliph
• 632–661 — Rashidun caliphate and rapid expansion
• 661–750 — Umayyad caliphate
• 750–1258 — Abbasid caliphate (Baghdad)
• 1054 / 1095–1291 — Parallel Christian schism and Crusades shape later Muslim–Christian memory
• 1924 — Abolition of the Ottoman caliphate

Key figures and texts

Muhammad is the final prophet in Islamic belief—the “Seal of the Prophets.” The Qur’an is recited as God’s speech in Arabic. It was compiled into a fixed text under the early caliphs (traditionally completed under Uthman, d. 656). Hadith collections (for example Bukhari and Muslim) record sayings and deeds of Muhammad and form a second major source for law and piety.

Later teachers matter for schools of law (madhahib) and theology: Abu Hanifa, Malik, al-Shafi‘i, and Ahmad ibn Hanbal for Sunni jurisprudence; Ja‘far al-Sadiq in Shi‘i tradition; and theologians and philosophers such as al-Ash‘ari, al-Ghazali, Ibn Sina (Avicenna), and Ibn Rushd (Averroes) in the wider intellectual story Catholics meet in medieval philosophy.

• Muhammad (c. 570–632) — prophet and founder of the community
• Abu Bakr, Umar, Uthman, Ali — first four caliphs
• Qur’an — primary scripture
• Hadith / Sunnah — prophetic tradition guiding practice and law
• Four Sunni schools of law; Ja‘fari and other Shi‘i legal traditions

Beliefs and doctrines

Islam’s core confession is tawhid: the absolute oneness of God. The shahada states that there is no god but God and Muhammad is his messenger. Jesus (‘Isa) is honored as a virgin-born prophet and Messiah in the Qur’anic sense, but not as eternal Son. Mainstream Islam denies the crucifixion as Christians confess it (Qur’an 4:157 is the usual reference). The Trinity is rejected as compromising God’s oneness.

Last things include bodily resurrection, judgment, paradise, and hell. Salvation language differs from Catholic grace and sacrament categories. Emphasis falls on faith, repentance, and deeds weighed by a merciful and just God. Sufi traditions add paths of interior purification; they are influential, but they are not identical with every Muslim’s practice.

• Tawhid — absolute monotheism
• Prophets — including Abraham, Moses, Jesus; Muhammad as final prophet
• Jesus — prophet, not incarnate God; crucifixion denied in mainstream teaching
• Qur’an as final revelation; earlier scriptures seen as altered or superseded in Islamic accounts
• Sunni / Shi‘a split — chiefly over rightful leadership after Muhammad

• Qur’an

  Surah 112, translation of Mustafa Khattab

  Surah 4:157, translation of Mustafa Khattab

  “He is Allah—One and Indivisible; Allah—the Sustainer needed by all. He has never had offspring, nor was He born. And there is none comparable to Him.”

  God is one

  Suggest a correction

  “We killed the Messiah, Jesus, son of Mary, the messenger of Allah.” But they neither killed nor crucified him—it was only made to appear so.”

  Jesus

  Suggest a correction

Practices and worship

The Five Pillars structure ordinary Sunni practice: shahada (witness), salat (prayer five times daily), zakat (almsgiving), sawm (fasting in Ramadan), and hajj (pilgrimage to Mecca if able). Friday congregational prayer and the mosque are central communal markers. Dietary law (halal), calendar feasts (Eid al-Fitr, Eid al-Adha), and local custom vary widely across cultures—from Indonesia to West Africa to the Arab world to Western diasporas.

• Five Pillars — confession, prayer, alms, Ramadan fast, hajj
• Mosque and Friday prayer
• Ramadan and the two Eids
• Halal dietary practice
• Sharia — moral/legal tradition with diverse schools and modern political meanings

Texts they cite

Muslims cite the Qur’an, not the New Testament, as the final standard. The usual texts in a conversation with Christians are the verses on God’s oneness (especially 112), the denial that God has a son, and 4:157, read as a denial that Jesus was crucified. Jesus, called ‘Isa, is a prophet and Messiah in the Qur’anic sense, born of Mary, and not God incarnate.

Catholics bring the Gospels’ passion narratives and the council definitions of Nicaea and Chalcedon: Jesus is the eternal Son, and he died and rose. Nostra Aetate (1965) says Muslims adore the one God. It does not say the two faiths teach the same thing about him.

• Qur’an 112 — oneness
• Qur’an 4:157 — the crucifixion verse
• Qur’an 19 — Mary and Jesus
• John 1:1–18 and the creeds, on the Christian side

  “In the beginning was the Word, and the Word was with God, and the Word was God. … The Word became flesh, and lived among us.”

Tradition and magisterium

Nostra Aetate speaks with respect of Muslims who adore the one God, living and subsistent. Dominus Iesus insists nonetheless on the unique mediation of Jesus Christ and the necessity of the Church for the fullness of salvation’s means.

A conversation with Muslims has to keep two things clear: courtesy toward Muslim neighbors, and the difference over the Trinity, the Incarnation, and the Cross. The texts to read on their side are the Qur’an, especially the confession that God is one and does not beget, and the verse that says Jesus was not crucified.

History and development

Centuries of conflict and exchange stand behind Nostra Aetate’s call for respect and dialogue, and Dominus Iesus later restates Christ’s uniqueness amid pluralist pressures.

What to know before dialogue

Learn what Muslims actually confess—tawhid, prophecy, the Qur’an, and the Five Pillars—before you turn to the Trinity or the Cross. Catholics and Muslims both confess one God, and they divide over who Jesus is; the conversation has to hold both facts at once.

• State shared theism and real differences.
• Defend Incarnation without straw men of Islam.
• Practice respectful witness.

Common misconceptions

Sources

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Revision history

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