The Christian doctrine of the Trinity (Latin: Trinitas, ‘threefold’) is the central doctrine concerning the nature of God in most Christian churches. This mysterious doctrine defines one God existing in three coequal, coeternal, consubstantial divine persons God the Father, God the Son Jesus Christ and God the Holy Spirit, three distinct persons (hypostases) sharing one essence/substance/nature (homoousion). As the Fourth Lateran Council declared, it is the Father who begets, the Son who is begotten, and the Holy Spirit who proceeds. In this context, one essence/nature defines what God is, while the three persons define who God is. This expresses at once their distinction and their indissoluble unity. Thus, the entire process of creation and grace is viewed as a single shared action of the three divine persons, in which each person manifests the attributes unique to them in the Trinity, thereby proving that everything comes “from the Father,” “through the Son,” and “in the Holy Spirit”.
This doctrine is called “Trinitarianism” and its adherents are called “Trinitarians”.While the developed doctrine of the Trinity is not explicit in the books that constitute the New Testament, the New Testament possesses a triadic understanding of God and contains a number of Trinitarian formulas (1 Pet. 1:2; 2Cor. 13:13).Though the Trinity is mainly a Christian concept, Judaism has had parallel views, especially among writings from the kabbalah tradition. The doctrine of the Trinity was used to oppose alternative views of how the three are related and to defend the church against charges of worshiping two or three gods.
The Old Testament has been interpreted as referring to the Trinity in many places. One of these is the prophecy about the Messiah in Isaiah 9. The Messiah is called “Wonderful Counselor, Mighty God, Everlasting Father, and Prince of Peace”. Some see this verse as meaning the Messiah will represent the Trinity on earth. This is because Counselor is a title for the Holy Spirit (Jn. 14:26), the Trinity is God, Father is a title for God the Father, and Prince of Peace is a title for Jesus. Also, Genesis 18–19 has been interpreted by Christians as a Trinitarian text. While the developed doctrine of the Trinity is not explicit in the books that constitute the New Testament, the New Testament contains a number of Trinitarian formulas, including Matt. 28:19, 2Cor. 13:14, 1Cor. 12:4–5, Eph. 4:4–6, 1Pet. 1:2, Rev. 1:4–6. Reflection by early Christians on passages such as the Great Commission: “Go therefore and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit” and Paul the Apostle’s blessing: “The grace of the Lord Jesus Christ and the love of God and the fellowship of the Holy Spirit be with you all”, leading theologians across history in attempting to articulate the relationship between the Father, Son, and Holy Spirit. Eventually, the diverse references to God, Jesus, and the Spirit found in the New Testament were brought together to form the doctrine of the Trinity.
In Trinitarian doctrine, one Godhead subsists in three persons and one substance. God exists as three persons but is one being, having a single divine nature. The members of the Trinity are co-equal and co-eternal, one in essence, nature, power, action, and will. As stated in the Athanasian Creed, the Father is uncreated, the Son is uncreated, and the Holy Spirit is uncreated, and all three are eternal without beginning. “The Father and the Son and the Holy Spirit” are not names for different parts of God, but one name for God because three persons exist in God as one entity. They cannot be separate from one another. Each person is understood as having the identical essence or nature, not merely similar natures.
May the grace of our Lord Jesus Christ, the love of God and the fellowship of the Holy Spirit continue to be with us now and at the hour of our death. Amen.