"Hear, O Israel! The LORD is our God, the LORD alone!" For a Jewish reader, these words settle the matter: God is one, so how can Christians worship Father, Son, and Holy Spirit?
Short answer: No. The Catholic Church confesses the Shema as the foundation of its faith: there is one God and no other. Christians believe in one God in three persons, not three gods. Jesus called the Shema the first commandment, and St. Paul restated it while naming Jesus the "one Lord." The Trinity is not a retreat from the Shema; it is what the God of the Shema revealed about Himself when He came among His people.
Key verses on the Shema and the Trinity
- "Hear, O Israel! The LORD is our God, the LORD alone!" (Deuteronomy 6:4)
- "Hear, O Israel! The Lord our God is Lord alone!" (Mark 12:29)
- "for us there is one God, the Father... and one Lord, Jesus Christ" (1 Corinthians 8:6)
- "Let us make human beings in our image, after our likeness." (Genesis 1:26)
- "The LORD says to my lord: 'Sit at my right hand'" (Psalm 110:1)
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
The Catechism grounds its teaching on the one God in the Shema. "God is unique; there is only one God" (CCC 200). "To Israel, his chosen, God revealed himself as the only One" (CCC 201). It even repeats an early Christian maxim: "If God is not one, he is not God" (CCC 228, quoting Tertullian).
The Trinity adds no gods. "We do not confess three Gods, but one God in three persons" (CCC 253). Each person "is God whole and entire" (CCC 253), and they are distinguished only by their relations to one another (CCC 255).
What Catholics do not teach:
- Three gods, or a God with parts. There are "three persons indeed, but one essence, substance or nature entirely simple" (CCC 202).
- That a man was promoted to godhood. Christians believe the eternal Son, who is God, became man. They do not worship a creature beside God.
- That the Trinity can be read off the Hebrew Scriptures alone. God's inmost being as Trinity was "inaccessible to reason alone or even to Israel's faith before the Incarnation of God's Son and the sending of the Holy Spirit" (CCC 237).
The Biblical Case
1. The Shema is the Church's creed too
"Hear, O Israel! The LORD is our God, the LORD alone! Therefore, you shall love the LORD, your God, with your whole heart" (Deuteronomy 6:4–5). The NABRE note lists other possible translations: "the Lord our God is one Lord"; "the Lord our God, the Lord is one"; "the Lord is our God, the Lord is one." On any rendering the point stands: "since the Lord alone is God, Israel must love him with an undivided heart." Catholics affirm every word.
Some Christians argue that the Hebrew echad ("one") implies a compound unity, since husband and wife "become one body" (Genesis 2:24), also echad in Hebrew. But it is the ordinary word for "one," so it cannot carry the argument.
2. Jesus called the Shema the first commandment
Asked which commandment is first, Jesus answered: "Hear, O Israel! The Lord our God is Lord alone!" (Mark 12:29). When the scribe agreed, "He is One and there is no other than he," Jesus told him, "You are not far from the kingdom of God" (Mark 12:32–34). Jesus never revised the Shema.
3. St. Paul restated the Shema with Jesus inside it
St. Paul affirms "there is no God but one" (1 Corinthians 8:4), then writes: "yet 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 NABRE note says this "rephrases the monotheistic confession of v. 4" and calls it "the earliest reference in the New Testament to Jesus' role in creation." Without adding a second god, St. Paul places Jesus on the Creator's side of creation.
4. Daniel's Son of Man, and Jesus before the Sanhedrin
Daniel sees "the Ancient of Days" enthroned, and then "One like a son of man" coming "with the clouds of heaven." This figure "received dominion, splendor, and kingship; all nations, peoples and tongues will serve him" (Daniel 7:9, 13–14). In the Hebrew Scriptures, it is "the LORD" who is "riding on a swift cloud" (Isaiah 19:1), and the worship of all nations belongs to Him alone. The rabbis felt the weight of the plural "thrones" in 7:9: Rabbi Akiva taught, "One throne is for Him and one throne is for David," and Rabbi Yosei rebuked him: "Akiva! Until when will you desacralize the Divine Presence by equating God with a person?" Rabbi Yosei's own answer was that "both thrones are for God" (Sanhedrin 38b).
At His trial the high priest asked Jesus, "Are you the Messiah, the son of the Blessed One?" He answered, "I am; and 'you will see the Son of Man seated at the right hand of the Power and coming with the clouds of heaven.'" The high priest replied, "You have heard the blasphemy" (Mark 14:61–64). Jesus was not condemned for claiming to be a mere man. He was condemned for claiming the throne beside God.
5. Hints in the Hebrew Scriptures, read in light of the New Testament
These are hints, not proofs; the NABRE notes deserve a hearing.
- Genesis 1:26. "Let us make." The note explains the plural as God presiding over "an assembly of heavenly beings." Christians have seen a hint of plurality in God.
- Genesis 18. "The LORD appeared to Abraham," who "saw three men" (Genesis 18:1–2). The note calls this "a narrative way of expressing the mysterious presence of God."
- Genesis 32. "A man wrestled with him until the break of dawn," and Jacob concluded, "I have seen God face to face" (Genesis 32:25, 31). The NABRE note explains "Peniel" as "the face of God."
- Isaiah 48:16. "Now the Lord GOD has sent me, and his spirit" (Isaiah 48:16). The note assigns these words to Cyrus, so the hint is faint.
- Psalm 110:1. "The LORD says to my lord." The note says the singer first addressed the king, while Jesus read "my lord" as the Messiah, "someone greater than David." In Mark 12, right after affirming the Shema, Jesus cites this psalm: "David himself calls him 'lord'; so how is he his son?" (Mark 12:35–37).
The Catechism's word is "traces" (CCC 237); the New Testament reveals what they only hint. Jesus says, "The Father and I are one" (John 10:30), and sends His disciples to baptize "in the name of the Father, and of the Son, and of the holy Spirit" (Matthew 28:19): one name. For the wider case, see Is the Trinity in the Bible?
Objections Answered
(a) "God's unity cannot be divided. Three persons means three, whatever you call it."
At its strongest: Maimonides wrote: "This God is one. He is not two or more, but one, unified in a manner which [surpasses] any unity that is found in the world." He is not one "in the manner of a general category which includes many individual entities, nor one in the way that the body is divided into different portions" (Mishneh Torah, Foundations of the Torah 1:7). The prayer book's version of his Thirteen Principles confesses that God "is unique, and there is no uniqueness like His in any manner" (Principle 2).
Answer: Catholics reject the very ideas Maimonides rules out here. God is not a category with several members, and He has no parts. The divine nature is "entirely simple" (CCC 202). The persons are not three beings sharing a genus; their distinction "resides solely in the relationships which relate them to one another" (CCC 255). Christians agree that God's unity is unlike any unity in the world. They believe that, in Jesus, God revealed His one life to be a life of eternal relation.
(b) "Genesis 1:26 is God addressing the angels. Christians read the Trinity into it."
At its strongest: The NABRE note itself points to a heavenly council. The rabbis felt the verse's weight: in the midrash, Moses asks, "why do you provide the heretics with basis for a claim?" and God answers, "Just write, and if someone wants to err, let him err" (Bereshit Rabbah 8:8). The same passage says God "consulted with the ministering angels."
Answer: Fair. The Church does not claim Genesis 1:26 proves the Trinity, which could not be known from Israel's faith before Christ (CCC 237). Christians read such passages in light of Jesus, as He did with Psalm 110. The real question is whether Jesus and St. Paul, who both confessed the Shema, also spoke of Jesus as Lord and Creator. They did.
(c) "Worship belongs to God alone. Christians worship a man."
At its strongest: God swears, "To me every knee shall bend; by me every tongue shall swear" (Isaiah 45:23). The fifth Principle holds that God "is the only One to Whom it is proper to pray."
Answer: Christians agree, which makes St. Paul's words striking. He applies that oath to Jesus: "at the name of Jesus every knee should bend... and every tongue confess that Jesus Christ is Lord, to the glory of God the Father" (Philippians 2:10–11). A Pharisee would never give God's glory to a creature. St. Paul could write this only because he believed Jesus belongs within the one God.
(d) "God is not a man. The Incarnation contradicts the Torah."
At its strongest: "God is not a human being who speaks falsely, nor a mortal, who feels regret" (Numbers 23:19). Through Hosea, God says, "For I am God and not a man" (Hosea 11:9). A God who becomes a man seems to be exactly what the prophets deny.
Answer: In context, Numbers 23:19 says God does not lie as mortals do; Hosea 11:9, that He will not act in wrath as a man would. Both deny human weakness in God, not God's power to come in human form, as Jacob confessed: "I have seen God face to face" (Genesis 32:31). The Church does not teach that God turned into a man or stopped being God. The Son "became truly man while remaining truly God" (CCC 464), "without ceasing to be God and Lord" (CCC 469). In His divine nature God remains "not a man"; in Christ He has also become one of us.
Jewish and Early Christian Sources
- Rabbi Akiva died reciting the Shema. The Talmud says he "prolonged his uttering of the word: One, until his soul left his body" (Berakhot 61b). Christians honor that witness to the one God.
- Rashi read the Shema as a hope: the LORD, now Israel's God, "will at some future time be the One (sole)" God of all peoples, citing Zephaniah 3:9 (Rashi on Deuteronomy 6:4). The Church cites that same verse as it awaits the day when all peoples will "serve him shoulder to shoulder" (Nostra Aetate 4).
- The Didache (late first or early second century), the earliest Christian manual outside the New Testament, directs: "baptize into the name of the Father, and of the Son, and of the Holy Spirit" (Didache 7).
- St. Ignatius of Antioch (Letter to the Ephesians 7 and 18, c. A.D. 107), a bishop of the generation after the apostles, calls Jesus "God existing in flesh" and writes, "For our God, Jesus Christ, was, according to the appointment of God, conceived in the womb by Mary" (newadvent.org).
- St. Justin Martyr (Dialogue with Trypho 62, second century) records Jewish teachers explaining "Let Us make" as God speaking "to Himself" or "to the elements." St. Justin answered from Genesis 3:22 ("as one of us") that God "conversed with some one who was numerically distinct from Himself" (newadvent.org).
- Tertullian (Against Praxeas 2, early third century), one of the first writers to use the word "Trinity" (Latin trinitas), insisted that it protects God's oneness: "the mystery of the dispensation is still guarded, which distributes the Unity into a Trinity," the three being "three, however, not in condition, but in degree" (newadvent.org).
Conclusion
Jews and Catholics share the Shema. We pray to the God of Abraham, Isaac, and Jacob, and we believe He is one. The disagreement is not whether God is one, but what God revealed about His oneness in Jesus.
If you are Jewish, we ask only that you read Mark 12 and 1 Corinthians 8 for yourself. There Jesus confesses the Shema as the first commandment, and St. Paul, a Pharisee, confesses it while naming Jesus the "one Lord." Then read Daniel 7 and Mark 14, and ask why the high priest heard blasphemy.
Come and see. The one God of the Shema, revealed in Jesus as Father, Son, and Holy Spirit, is worshiped today as one God in the Catholic Church. If Jesus is Israel's Messiah, His Church is not a foreign religion. It is the home He built for Israel and the nations, and He sent His Jewish apostles 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). With respect and love, we invite you to meet the Messiah 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 Catholics believe Jews worship the same God? Yes. The Jewish faith "is already a response to God's revelation in the Old Covenant" (CCC 839). Yet that revelation reaches its fullness in Christ, and "all salvation comes from Christ the Head through the Church which is his Body" (CCC 846).
Does echad prove the Trinity? No. It can describe a unity of several (Genesis 2:24), but it is the ordinary Hebrew word for "one."
Is the Trinity taught in the Old Testament? Only in traces. The Church says it was inaccessible "even to Israel's faith before the Incarnation" (CCC 237).
Sources
Scripture (NABRE, bible.usccb.org): Genesis 1:26 (with note); Genesis 2:24; Genesis 18:1–2 (with note); Genesis 32:25, 31 (with note); Numbers 23:19; Deuteronomy 6:4–5 (with notes); Psalm 110:1 (with note); Isaiah 19:1; Isaiah 45:23; Isaiah 48:16 (with note); Daniel 7:9, 13–14; Hosea 11:9; Matthew 28:19; Mark 12:29–37; Mark 14:61–64; John 10:30; 1 Corinthians 8:4–6 (with note); Philippians 2:10–11.
Catechism of the Catholic Church (vatican.va): 200, 201, 202, 228; 237, 253, 255; 464, 469; 839, 846.
Church documents (vatican.va): Second Vatican Council, Nostra Aetate 4.
Church Fathers (newadvent.org): Didache 7; Ignatius of Antioch, Letter to the Ephesians 7, 18; Justin Martyr, Dialogue with Trypho 62 (ANF vol. 1); Tertullian, Against Praxeas 2 (ANF vol. 3).
Jewish sources (sefaria.org): Maimonides, Mishneh Torah, Foundations of the Torah 1:7 (trans. Eliyahu Touger); Thirteen Principles, Siddur Ashkenaz (translation based on the Metsudah siddur); Bereshit Rabbah 8:8 (Sefaria Midrash Rabbah, 2022); Babylonian Talmud, Berakhot 61b and Sanhedrin 38b (William Davidson Edition); Rashi on Deuteronomy 6:4 (Rosenbaum and Silbermann); Deuteronomy 6:4 and Genesis 2:24 (Hebrew text).