As a doctrine and a liturgical formula, the Trinity is not developed in the Bible, nor are the distinctions between the three “persons” always clearly articulated. Nevertheless, the concept of God as Father, Son, and Spirit is present.
The stress in Scripture is always on the unity of God. The Father and the Son are one (John 10:30; 17:21); they glorify one another (John 17:1). The Father and the Spirit are one, for the Spirit “searches all things, even the deep things of God,” and knows his inward being (1 Cor. 2:10). The Son and the Spirit are one, since the Father sends the Spirit in the Son’s “name” (John 14:26). The Word and the Spirit are one. When the psalmist declares, “By the word of the Lord were the heavens made, their starry host by the breath of his mouth” (Ps. 33:6), the principle of poetic parallelism suggests that the word of God and the Spirit (ruḥ, “breath”) of God are the same. Similarly in the New Testament, a comparison of the parallel passages, Ephesians 5:18–20 and Colossians 1:6, reveals the identity of the Spirit and the Word, and Paul says specifically that “the Lord is the Spirit” (2 Cor. 3:17). The apostolic church remained committed to the uncompromising monotheism of the Jewish faith, expressed in the Shma‘ of synagogue worship: “Hear, O Israel: The Lord our God, the Lord is one” (Deut. 6:4), although the phrase is more accurately translated “Yahweh is our God, Yahweh alone.” When the Trinitarian formulation, or an approximation thereof, appears in the New Testament, there is usually a strong suggestion that the different terms used express the same living reality.
The Trinitarian formula, so familiar in Christian worship, is found in Scripture only in Matthew 28:19, where the risen Christ commissions the apostles to make disciples of all people, baptizing them “in the name of the Father and of the Son and of the Holy Spirit.” The use of the word name in the singular suggests that the unity of the three “persons,” rather than their distinction, is in view, and in actual practice the early church usually baptized into Jesus Christ, or into his name (Acts 2:38; 8:12; 19:5; Rom. 6:3; 1 Cor. 1:13).
The Trinitarian formula is also implicit in certain expressions of the apostle Paul, although other words may be substituted for the classic terms Father and Son. Writing to the Corinthians, he mentions varieties of gifts (charismata) but the same Spirit, varieties of ministries or service (diakoniai) but the same Lord, and varieties of effects or workings (energēmata) but the same God (1 Cor. 12:4–6). Again, his wording suggests a stress on the oneness of the source of the church’s power. In Ephesians 4:4–6 Paul proclaims “one body and one Spirit,” the life or breath of the body; “one Lord, one faith, one baptism” into Jesus the Son; and “one God and Father of all.” The Trinitarian pattern is repeated within the clause applying to the Father, who is “over all and through all and in all.” Thinking in Trinitarian terms, God is over all as Creator King, through all in the pervasive life-giving presence of the Spirit, and in all as Christ in the corporate church (“the hope of glory,” Col. 1:27). Paul’s familiar benediction of 2 Corinthians 13:14, often used in Christian worship, commends his readers to “the grace of the Lord Jesus Christ, and the love of God, and the fellowship [koinōnia, participation or communion] of the Holy Spirit.”
In these expressions, we see not the attempt to formulate a doctrine of God in three persons (the need for that was perceived later in the church’s history) but the effort to convey, within the limitations of human language, something of the fullness of the workings of the divine in relation to his worshipers. In the Spirit he offers his people life, gifts, communion; in the Son he quickens in them service, obedience, and faith; in the Father he governs and provides for them in his authority, creative working, and steadfast love. In every way he moves toward them to dwell in their midst, the covenant Lord with his covenant people, that in the end “God may be all in all” (1 Cor. 15:28).