The Trinity

The Nicene Creed, as expanded at the Council of Constantinople in 381, confesses one God, the Father Almighty; one Lord Jesus Christ (peace be upon him), "true God from true God, begotten, not made, consubstantial with the Father"; and the Holy Spirit, "who with the Father and the Son is adored and glorified".

The Athanasian Creed, a Latin creed most likely from the late fifth or early sixth century and so written at least a century after Athanasius, states: "we worship one God in Trinity, and Trinity in Unity; neither confounding the persons nor dividing the substance" and "the Father is God, the Son is God, and the Holy Spirit is God; and yet they are not three Gods, but one God."

The Catechism of the Catholic Church (CCC 234) calls the Trinity "the central mystery of Christian faith and life", and CCC 253 says: "We do not confess three Gods, but one God in three persons, the 'consubstantial Trinity'." CCC 237 calls it "a mystery of faith in the strict sense", one of the "mysteries that are hidden in God, which can never be known unless they are revealed by God".

Trinitarian scholars do not claim that any single verse states the full doctrine. Their case is that several lines of New Testament evidence, read together, require it: there is one God; the Father, Jesus (peace be upon him) and the Spirit are each presented as divine; and the three are distinct from each other.

One "name" (singular) is given for three. Trinitarians read this as one divine name shared by three persons.

The Word is both "with God" and "God", which Trinitarians read as distinct persons sharing one divine nature. John 1:14 identifies the Word with Jesus.

In John 10:31 to 33 the hearers pick up stones because, they say, "you, being a man, make yourself God". Trinitarians cite this as evidence that the claim was understood as divine.

They also cite the Old Testament "preparation": the plural "Let us make man" (Genesis 1:26), personified Wisdom (Proverbs 8) and the title "Mighty God" (Isaiah 9:6). The Catholic Encyclopedia (1912) presents these as stages of preparation rather than a stated doctrine.

The Hebrew Bible never states that God is three persons. The Catholic Encyclopedia itself, defending the doctrine, treats Old Testament passages as "preparation" and does not claim an explicit statement. Jewish interpretation, which reads the same texts, has never drawn a Trinity from them. The word "Trinity" appears in no book of either Testament; it is first found in Greek (trias) in Theophilus of Antioch about 180 CE and in Latin (trinitas) in Tertullian.

Asked which commandment is first, Jesus (peace be upon him) quoted the Shema, the central confession of Jewish monotheism, and did not add to it. The scribe answers in Mark 12:32: "he is one, and there is none other but he".

In John 17:3 Jesus calls the Father "the only true God" and distinguishes himself as the one sent. In John 14:28 the Father is "greater than I". In Mark 13:32 the Son does not know the hour, which the Father alone knows. In Mark 10:18 he declines even the title "good", reserving it for God.

Trinitarian theology answers these verses by distinguishing Christ's human nature from his divine nature, so that he speaks some words as man and others as God. That distinction was defined at Chalcedon in 451, centuries after the Gospels were written. Whether the Gospel writers had it in mind is a matter of interpretation, and it is disputed.

The doctrine was formulated in stages. The Council of Nicaea (325), called by the Emperor Constantine, declared the Son homoousios, "of one substance", with the Father, against Arius, who taught that the Son was created. Eusebius of Caesarea reports that the term was put forward by Constantine himself. The debate continued for decades, and several later councils favored Arian-leaning creeds.

The Council of Constantinople (381), called by the Emperor Theodosius I, with about 150 bishops and no Western representation, expanded the creed's section on the Holy Spirit. Only from this point was the full doctrine of three co-equal persons set out in a conciliar creed. Historians generally describe the Trinity as a doctrine developed in the fourth century; Trinitarians reply that the councils defined what was already believed. The second point is disputed.

The King James Version contains the clearest Trinitarian verse in the Bible:

Modern critical texts do not contain it. The World English Bible and the Catholic New American Bible read only:

The extra words, known as the Johannine Comma, are absent from the early Greek manuscripts. Bruce Metzger traces the first mention to the fourth-century Latin treatise Liber Apologeticus; it appears in Latin manuscripts from the sixth century. The Nestle-Aland edition knows of eight Greek manuscripts that contain it, all late. Erasmus left it out of his first two Greek New Testaments because his Greek manuscripts lacked it, and added it in his 1522 edition, while expressing doubt about it in his Annotations. Modern Catholic and Protestant translations, including the RSV, the New English Bible and the New American Bible, leave it out of the main text.

The Quran addresses the Trinity directly. It honors Jesus (peace be upon him) as the Messiah, a messenger and a word from God, and Mary (peace be upon her) as a woman of truth, while denying that God is three or has a son.

Quran 5:75 makes a practical point: Jesus and his mother "both used to eat food", sharing the needs of every created being. Surah 112 sets out the alternative in four verses: God is One, the Eternal Refuge, neither begetting nor begotten, with none comparable to Him.