"The Qur'an says they disbelieve who call God 'the third of three.' If you worship the Father, the Son, and the Holy Spirit, how is that not three gods?" Muslims ask this out of real zeal for God's oneness.
Short answer: No. Christians worship one God, not three. What the Qur'an rejects (three gods, God as one part of three, Mary as a goddess, God taking a wife and fathering a child) Christians reject too. The Trinity means that the one, undivided God is Father, Son, and Holy Spirit, each fully God, not three parts and not three deities.
Key verses on the Trinity and God's oneness
- "Hear, O Israel! The LORD is our God, the LORD alone!" (Deuteronomy 6:4)
- "there is no God but one" (1 Corinthians 8:4)
- "baptizing them in the name of the Father, and of the Son, and of the holy Spirit" (Matthew 28:19)
- "In the beginning was the Word, and the Word was with God, and the Word was God." (John 1:1)
- "The grace of the Lord Jesus Christ and the love of God and the fellowship of the holy Spirit be with all of you." (2 Corinthians 13:13)
Scripture quotations are from the New American Bible, Revised Edition (NABRE), © 2010, 1991, 1986, 1970 Confraternity of Christian Doctrine, Washington, D.C. Used by permission. All rights reserved.
What Catholics Actually Teach
First, the Qur'an in its own words (Sahih International, quran.com). "They have certainly disbelieved who say, 'Allāh is the third of three.' And there is no god except one God" (5:73). The translators' note explains: "i.e., one part of three, referring to the Christian concept of trinity." Elsewhere: "And do not say, 'Three'; desist - it is better for you. Indeed, Allāh is but one God. Exalted is He above having a son" (4:171). God will ask Jesus, "did you say to the people, 'Take me and my mother as deities besides Allāh?'" (5:116). And: "He neither begets nor is born, Nor is there to Him any equivalent" (112:3–4). Ibn Kathir's commentary (abridged) reports that Mujahid applied 5:73 to the Christians in particular, while as-Suddi linked it to taking Jesus and his mother as gods, "thus making Allah the third in a trinity."
The concern is God's absolute oneness, and Catholics share it. "The Trinity is One. We do not confess three Gods, but one God in three persons" (CCC 253). "The divine persons do not share the one divinity among themselves but each of them is God whole and entire" (CCC 253). The Church confesses "one essence, substance or nature entirely simple" (CCC 202, quoting the Fourth Lateran Council). The Athanasian Creed sums it up: "We worship one God in the Trinity and the Trinity in unity, without either confusing the persons or dividing the substance" (CCC 266).
What Catholics do not teach (here we agree with the Qur'an's denials):
- Three gods. "We do not confess three Gods" (CCC 253).
- God as "one part of three." God has no parts. Each person is "God whole and entire," and the divine nature is "entirely simple."
- Mary as a goddess. Mary called herself "the handmaid of the Lord" (Luke 1:38) and God "my savior" (Luke 1:47). Her honor "differs essentially from the adoration which is given to the incarnate Word and equally to the Father and the Holy Spirit" (CCC 971).
- That God took a wife or fathered a child. "God is pure spirit in which there is no place for the difference between the sexes" (CCC 370).
The Biblical Case
1. Jesus Himself confessed one God
Asked for the first commandment, Jesus quoted Israel's creed: "Hear, O Israel! The Lord our God is Lord alone!" (Mark 12:29). God says, "I am the first, I am the last; there is no God but me" (Isaiah 44:6). The apostles kept this: "there is no God but one" (1 Corinthians 8:4). St. James even says, "You believe that God is one. You do well" (James 2:19).
2. One name, not three
Jesus sent His apostles out "baptizing them in the name of the Father, and of the Son, and of the holy Spirit" (Matthew 28:19). "Name" is singular. The Catechism draws the point: Christians are baptized "not in their names, for there is only one God" (CCC 233).
3. God's Word is God, not a second god
"In the beginning was the Word, and the Word was with God, and the Word was God" (John 1:1). The Word is not a creature, because "All things came to be through him" (John 1:3). And He is not a second god, since there is only one. So the Word is God's own eternal Word, "with God" and truly God. The Qur'an itself calls Jesus "His word which He directed to Mary" (4:171). Muslims and Christians read that phrase differently, but both use it.
4. Father, Son, and Spirit act together and remain distinct
At Jesus' baptism, He "saw the Spirit of God descending like a dove," and a voice said, "This is my beloved Son" (Matthew 3:16–17). St. Paul blesses in the same threefold pattern: "The grace of the Lord Jesus Christ and the love of God and the fellowship of the holy Spirit be with all of you" (2 Corinthians 13:13; 13:14 in some Bibles). And St. Paul, a Jew who prayed the Shema daily, divides its very words between Father and Son without adding a second God: "for us there is one God, the Father, from whom all things are and for whom we exist, and one Lord, Jesus Christ, through whom all things are and through whom we exist" (1 Corinthians 8:6). The Creator's work is credited to both. That is not three gods; it is the one God of Israel, revealed more fully.
Objections Answered
(a) "Three persons who are each God add up to three gods."
At its strongest: If the Father is God, the Son is God, and the Spirit is God, simple arithmetic gives three. The translators' note on 112:1 describes God as "indivisible with absolute and permanent unity." Any "three" in God seems to break that unity.
Answer: Catholics also hold that God is indivisible, "entirely simple" (CCC 202). The persons are not three beings sharing out one nature. Each is the whole divine nature, and they differ only in relation: "the Father is wholly in the Son and wholly in the Holy Spirit" (CCC 255). "One" and "three" count different things: one divine "substance" and three persons (CCC 252). That is a mystery known by revelation, not a contradiction. "God is one but not solitary" (CCC 254).
(b) "Christians took Jesus and Mary as gods" (5:116).
At its strongest: Qur'an 5:116 pictures Jesus denying that he ever said, "Take me and my mother as deities besides Allāh?" As-Suddi read 5:73 the same way. And some Christians in history did honor Mary excessively.
Answer: If that is the target, Catholics reject it too. In the fourth century, St. Epiphanius denounced a small sect, the Collyridians, "for their sacrificial offering of cakes to Mary," and laid down the rule that Mary is to be honored while only the Father, Son, and Holy Spirit are adored (Catholic Encyclopedia).
(c) "God does not beget, so He cannot have a Son" (112:3).
At its strongest: "How could He have a son when He does not have a companion [i.e., wife] and He created all things?" (6:101). A "Son" of God seems to lower God to the level of creatures.
Answer: Christians agree that God has no wife and does not reproduce (CCC 370). The Creed calls the Son "eternally begotten of the Father... begotten not made, consubstantial with the Father" (CCC 242): an eternal relation within the one God, like a word that comes forth from a mind without division or time. And Jesus' human conception was God's creative act, not a union: "The holy Spirit will come upon you, and the power of the Most High will overshadow you" (Luke 1:35).
(d) "The proof-text was forged, and the word 'Trinity' is not even in the Bible."
At its strongest: The King James Version's 1 John 5:7 contains a line naming three witnesses in heaven (the Father, the Word, and the Holy Ghost) who are one, and that line is missing from the early Greek manuscripts. If Christians had to add a verse to prove the Trinity, the doctrine must be a later invention. And the word "Trinity" appears nowhere in Scripture.
Answer: Both facts are true, and neither helps the objection. The Catholic Bible quoted here does not contain that added line at all: it reads "So there are three that testify, the Spirit, the water, and the blood" (1 John 5:7–8). No Catholic argument rests on it. The case rests on texts no one disputes: one God (Mark 12:29), one name of Father, Son, and Holy Spirit (Matthew 28:19), the Word who "was God" through whom "all things came to be" (John 1:1–3), and one God the Father with one Lord Jesus Christ (1 Corinthians 8:6). As for the word, "Trinity" is a summary term for what these verses teach together. The question is whether the reality is taught, and the Church was teaching it, and baptizing into it, long before Nicaea.
The Early Church Agrees
Christians confessed Father, Son, and Holy Spirit as the one God from the first generations, and denied "three gods" before the Qur'an and after it.
- The Didache (late first or early second century, date approximate) gives the baptismal rule: "baptize into the name of the Father, and of the Son, and of the Holy Spirit" (Didache 7), the exact formula of Matthew 28:19.
- St. Theophilus of Antioch (To Autolycus II.15, c. AD 180), the earliest surviving Christian writer known to use the word, says the first three days of creation "are types of the Trinity, of God, and His Word, and His wisdom" (newadvent.org).
- Tertullian (Against Praxeas 2, c. AD 213) speaks of the economy "which distributes the Unity into a Trinity," "the Father, the Son, and the Holy Ghost: three, however, not in condition, but in degree; not in substance, but in form; not in power, but in aspect" (newadvent.org). One substance, one power: not three gods.
Then, from the third century to the eighth:
- Pope St. Dionysius of Rome (letter of about AD 260, quoted by St. Athanasius) taught that Christ's true disciples "know well that a Triad is preached by divine Scripture, but that neither Old Testament nor New preaches three Gods" (De Decretis 26).
- St. John of Damascus (eighth century), who lived under Muslim rule in Damascus: "we do not speak of three Gods, the Father, the Son, and the Holy Spirit, but rather of one God, the holy Trinity" (Exposition of the Orthodox Faith I.8).
Conclusion
Muslims rightly insist that God is One and that no creature may share His worship. Catholics insist on the same. The real question is not whether God is one, but who the one God has revealed Himself to be.
We invite you to read the Gospel of John slowly and meet the Word who was "with God" and "was God." For the wider biblical case, see Is the Trinity in the Bible?
Come and see. The one God, Father, Son, and Holy Spirit, whom Christians have confessed since the apostles, without ever confessing three gods, is worshiped today in the Catholic Church. Jesus did not leave only a message. He founded a Church and sent her to "make disciples of all nations, baptizing them in the name of the Father, and of the Son, and of the holy Spirit" (Matthew 28:19). That Church is the Catholic Church, and she teaches that "all salvation comes from Christ the Head through the Church which is his Body" (CCC 846). We invite you to meet Jesus in the Catholic Church.
Your next step: Come to Mass this Sunday at your local Catholic church. You can find one near you at MassTimes.org. Everyone is welcome; if you're not yet Catholic, pray with us but don't receive Communion yet. When you're ready to become Catholic, call the parish office and ask about OCIA, the Order of Christian Initiation of Adults. They will walk you through every step. Read our guide: How Do I Become Catholic? Not ready yet? Get our free pocket guide below and keep learning.
FAQ
Do Christians believe God has a wife? No. God "is neither man nor woman: he is God" (CCC 239). Catholics call Mary "Mother of God" because the child she bore is God the Son made man. She gave Him His human nature, not His divinity, and she remains a creature (see Is Mary the Mother of God?).
Isn't the Trinity "associating partners" with God? That would mean putting a creature or another god beside God. The Son and the Spirit are not creatures added to God; they are the one God.
Which Qur'an translation is quoted here? Sahih International, as published on quran.com, with its own bracketed words and notes.
Sources
Scripture (NABRE, bible.usccb.org): Deuteronomy 6:4; Isaiah 44:6; Matthew 3:16–17; Matthew 28:19; Mark 12:29; Luke 1:35, 38, 47; John 1:1, 3; 1 Corinthians 8:4, 6; 2 Corinthians 13:13; James 2:19; 1 John 5:7–8.
Qur'an (Sahih International, quran.com): 4:171; 5:73; 5:116; 6:101; 112:1–4. Tafsir Ibn Kathir (abridged) on 5:73.
Catechism of the Catholic Church (vatican.va): 202; 233, 239, 242, 252, 253, 254, 255, 266; 370; 846; 971.
Church Fathers (newadvent.org): Didache 7; Theophilus of Antioch, To Autolycus II.15; Tertullian, Against Praxeas 2; Athanasius, De Decretis 26, quoting Dionysius of Rome (NPNF2 vol. 4); John of Damascus, Exposition of the Orthodox Faith I.8 (NPNF2 vol. 9). Also: Catholic Encyclopedia, "Devotion to the Blessed Virgin Mary".