There are very few doctrines which undergird the Christian life like the doctrine of the Trinity. And yet, in the Stone-Campbell movement, few foundational doctrines have been as historically controversial. Part of the reason for the resistance to the doctrine of the Trinity in our movement is because of the emergence of our tradition at a time when the classical doctrines of the faith were coming under fire. Groups like Deists and Unitarians attacked the doctrine, and primitivist/restorationist thinkers (like Campbell and Stone) yearned for a simpler, biblical language that captured the personal aspects of God, rather than the tight theological formulations of Protestant Scholasticism. In other words, dogmatic systematic thinking on the Trinity was “out,” and calling Bible stuff by Bible names was “in.” It didn’t help that the word Trinity is famously absent from Scripture. Readers interested in the reception of the doctrine in our early history are urged to consult the entry on “God, Doctrine of” written by Paul M. Blowers in The Encyclopedia of the Stone-Campbell Movement.

And yet, the theology of the doctrine is omnipresent in Scripture. The Old Testament constantly insists that there is only one God, the self-revealed Creator, who must be worshiped and loved exclusively (Deut 6:4-5; Isa 44:6-45:25). The New Testament agrees (Mark 12:29-30; 1 Cor 8:4; Eph 4:6; 1 Tim 2:5) but speaks of three personal agents, Father, Son, and Holy Spirit, working together in the manner of a team to bring about salvation (Rom 8; Eph 1:3-14; 2 Thess 2:13-14; 1 Pet 1:2).

The Scripture speaks to the deity of the three members of the Godhead: Father, Son, and Holy Spirit. For example, there are the myriad passages which demonstrate that God is Father (e.g., John 6:27; Titus 1:4). Then there are texts which prove the deity of Jesus Christ, like John 1 (“the word was God”), John 8:58 (“before Abraham was born, I am”), Col 2:9 (“in Christ all the fullness of Deity lives in bodily form”), Heb 1:3 (“the Son is the radiance of God’s glory and the exact imprint of his being”), Titus 2:13 (“our great God and Savior Jesus Christ”)—not to mention the explicit worship Christ willingly received from his disciples (Luke 24:52; John 20:28) and the charges of blasphemy leveled against him for making himself equal with God (Mark 2:7). Then we have similar texts which assume the deity of the Holy Spirit, calling him an “eternal Spirit” (Heb 9:14) and using “God” interchangeably with the “Holy Spirit” (1 Cor 3:16; 6:19; Acts 5:3-4) without a second thought.

The shape of Trinitarian orthodoxy is finally rounded off by texts that hint at the plurality of persons in the Godhead (Gen 1:1-3, 26; Ps 2:7; Dan 7), texts like 1 Cor 8:6 which place Jesus Christ as Lord right in the middle of Jewish Shema, and dozens of texts that speak of the Father, Son, and Holy Spirit in the same breath, equating the three in rank, while assuming distinction of personhood (Matt 28:19; Gal 4:6; 1 Cor 12:4-6; 1 Pet 1:1-2; 2 Cor 2:21-22; 13:14; Eph 1:13-14; 2:18, 20-22; 3:14-17; 4:4-6; 5:18-20; 6:10-18).

Some people contend the doctrine is a contradiction. It is not for reasons beyond the scope of this post. But indeed the doctrine of the Trinity is a mystery. The historic formulation of the Trinity (derived from the Latin word trinitas, meaning “threeness”) seeks to circumscribe and safeguard this mystery (not explain it; that is beyond us), and it confronts us with perhaps the most difficult thought that the human mind has ever been asked to handle. It is not easy, but it is true.

The church struggled with this profoundly in the first four centuries in order to be faithful to the clear teaching of Scripture that God is one and also that the Father, the Son, and the Holy Spirit are all divine. The Christian formula for the Trinity—God is one essence in three persons—may seem to be contradictory because we are accustomed to seeing one being as one person. We cannot conceive of how one being could be contained in three persons and still be only one being. To that extent, the doctrine of the Trinity in this formulation is mysterious; it boggles the mind to think of a being who is absolutely one in his essence yet three in person.

But embrace this doctrine we must, for it is the most practical of doctrines for the Christian faith. Why? It is the foundation of the gospel. Without the love of the Father, the coming of the Son, and the regenerating power of the Holy Spirit, there simply could be no salvation.

During his Farewell Discourse, Jesus explained to Philip that to see him is to see the Father (John 13:8-11). Yet he is not himself the Father; otherwise, he could not have been the way to the Father (John 14:6). He is also “in” the Father, and the Father is “in him.” This mutual indwelling is, as the theologians say, “ineffable”—beyond our ability to understand. Yet it is not beyond faith’s ability to believe.

Moreover, the Holy Spirit lies at the heart of this bond between the Father and his Son. But now the Father has sent his Son (who is “in” the Father). Such is the love of the Father and the Son for believers that they will come to make believers their home.

How so? The Father and Son come to indwell the believer through the indwelling of the Holy Spirit (14:23). He glorifies Christ (16:14). He takes what belongs to Christ, given to him by the Father, and shows it to us. Later, when we have the privilege of overhearing our Lord’s prayer, Jesus similarly speaks about the intimacy of fellowship with God that sustained him so wonderfully: “You, Father, are in me, and I in you” (John 17:21).

I hope you see the point—to speak of the Trinity is to speak of the gospel and our adoption as God’s children. To be saved is to be in union with Christ. And to be united with Christ is to share in a union created by the indwelling of the Spirit of the incarnate Son who himself is “in” the Father as the Father is “in” him. Union with Christ means nothing less than fellowship with all three persons of the Trinity. It is not that the divine nature is infused into believers. Our union with Christ is spiritual and personal—effected by the indwelling of the Spirit of the Son of the Father.

Rather than eschew the goodness of the Trinity then, we ought to embrace it. It is the way God has disclosed Godself. To understand the Trinitarian God is to understand the divine dance of salvation.