Is There Only One God? What Judaism, Christianity, and Islam Teach

Monotheism isn't just a belief in Judaism—it's the defining conviction of the entire tradition. The Shema, recited daily by observant Jews, is drawn directly from Deuteronomy 6:4 and declares the absolute oneness of God in the most concise possible terms Deuteronomy 6:4. This isn't a philosophical abstraction; it's a lived, liturgical commitment repeated morning and evening.

The prohibition in Deuteronomy 5:7 reinforces this: no other gods are to be acknowledged or worshiped alongside the God of Israel Deuteronomy 5:7. The prophetic literature deepens the claim. Isaiah 44:6 presents God as self-identifying as the first and the last, with no competitor Isaiah 44:6. First Chronicles 17:20 echoes this with the declaration that there is no other God but the God of Israel 1 Chronicles 17:20.

Zechariah 14:9 adds an eschatological dimension—a future in which God's singular sovereignty is universally recognized, with one name and one worship Zechariah 14:9. Medieval Jewish philosopher Maimonides (1138–1204) codified divine unity as the second of his Thirteen Principles of Faith, insisting God's oneness is utterly unlike any numerical or composite unity. There's no serious internal debate in Judaism about whether God is one; the debates concern how to articulate that oneness philosophically.

Christianity unambiguously affirms that there is only one God—it inherits this directly from its Jewish roots and the Hebrew scriptures. Paul's letter to the Corinthians states plainly that 'to us there is but one God, the Father, of whom are all things' 1 Corinthians 8:6. This monotheistic commitment has never been in serious dispute within mainstream Christianity.

Where Christianity diverges—and where centuries of theological controversy have been generated—is in its Trinitarian understanding of that one God. The Council of Nicaea (325 CE) formalized the teaching that Father, Son, and Holy Spirit are three distinct persons sharing one divine essence. Paul's statement in 1 Corinthians 8:6 is itself suggestive of this complexity: it names both 'one God, the Father' and 'one Lord Jesus Christ' in the same breath 1 Corinthians 8:6, a juxtaposition that Trinitarian theologians like Athanasius used to argue for Christ's full divinity within a monotheistic framework.

Critics—including Jewish and Muslim thinkers—have argued that the Trinity compromises genuine monotheism. Most Christian theologians, from Augustine of Hippo (354–430) to Karl Barth (1886–1968), have insisted it does not: the three persons are not three gods but one God in three modes of being or relation. It's a distinction that remains contested across traditions, but within Christianity itself, the answer to 'is there only one God?' is an unequivocal yes.

Tawhid—the absolute oneness of God—is arguably the single most central doctrine in all of Islamic theology. It's not one belief among many; it's the foundation everything else rests on. The Quran returns to this theme repeatedly and with striking directness. Quran 2:163 states: 'your god is one God' and immediately rules out any other deity Quran 2:163. Quran 20:98 reinforces this: 'Your god is only Allāh, except for whom there is no deity' Quran 20:98.

Quran 38:5 is particularly interesting—it records the mockery of the Prophet Muhammad's opponents who found the idea of a single God astonishing: 'Has he made the gods only one God? Indeed, this is a curious thing' Quran 38:5. The verse preserves the scandal that strict monotheism caused in a polytheistic Arabian context, and implicitly validates that scandal as the correct position.

Islamic theology, developed by scholars like Al-Ash'ari (874–936) and later Al-Ghazali (1058–1111), distinguishes between tawhid al-rububiyya (oneness of lordship) and tawhid al-uluhiyya (oneness of worship). Both are required. Associating partners with God—shirk—is considered the gravest possible sin in Islam. The Christian Trinity and any veneration of saints or intermediaries are viewed by mainstream Islamic theology as compromising tawhid, even if those traditions don't intend polytheism.

Judaism centrally proclaims God’s oneness in the Shema: “Hear, O Israel: The LORD our God is one LORD,” affirming exclusive, indivisible monotheism Deuteronomy 6:4.

The Tanakh insists there is no other god besides the God of Israel: “I am the first and I am the last, And there is no god but Me,” underscoring absolute uniqueness Isaiah 44:6.

Israel is commanded to have no other gods, which excludes rival deities from devotion and worship Deuteronomy 5:7.

Prophetic hope envisions universal recognition of this one God: “in that day there shall be one GOD with one name,” stressing worldwide acknowledgment of divine unity Zechariah 14:9.

Liturgical and theological monotheism in Judaism is therefore unequivocal and exclusive, with no partners or equals to God Deuteronomy 6:4Isaiah 44:6.

The New Testament affirms monotheism: “to us there is but one God, the Father, of whom are all things,” marking continuity with Israel’s confession of one God 1 Corinthians 8:6.

The same verse names “one Lord Jesus Christ, by whom are all things,” a paired confession that Christians read in light of monotheism, generating intra-Christian discussions on how this fits divine unity 1 Corinthians 8:6.

Early Christian proclamation thus holds a single God while confessing Jesus as “Lord,” framing worship and creation language within a monotheistic horizon 1 Corinthians 8:6.

The Qur’an declares: “And your god is one God. There is no deity [worthy of worship] except Him,” an explicit and foundational statement of tawhid (divine oneness) Quran 2:163.

It reiterates exclusivity: “Your god is only Allah, except for whom there is no deity,” emphasizing that worship belongs to God alone Quran 20:98.

Early Meccan opposition recognized the Prophet’s call as consolidating all supposed gods into one, highlighting Islam’s uncompromising monotheism Quran 38:5.