The Christian faith is fundamentally a trinitarian faith. In other words, the doctrine of the Trinity is absolutely fundamental and central to our faith and life. So, just what is the doctrine of the Trinity? The doctrine of the Trinity is the teaching that there is only one God who eternally exists in three distinct, yet coequal, persons: the Father, the Son, and the Holy Spirit. In other words, there is only one God, which refers to Being (the Godhead) and within the Godhead there eternally exists three distinct and coequal Persons (the Father, the Son, and the Holy Spirit). James White has put it this way: “Within the one Being that is God, there exists eternally three coequal and coeternal persons, namely, the Father, the Son, and the Holy Spirit.”
The Father is not the Son and the Son is not the Holy Spirit and the Holy Spirit is not the Father. Together, however, they are one God, not three gods (i.e. Tritheism). Each Person is fully God, not 1/3 of God. Although this may be a mystery to our finite minds, nonetheless, the Scriptures reveal this wonderfully glorious truth (see Scripture compilation below). White’s words are helpful at this point:
These technical definitions are generally negative; that is, they tell us more about what the Trinity isn’t than what it is. This shouldn’t be surprising, however. We must always remember that we are trying to define and describe something that is absolutely, universally unique. It is far easier to say, ‘I don’t mean this,’ than it is to say, ‘Well, it’s like this,’ since there is nothing in the created universe that really, fully is like an absolutely unique thing [cf. Isa. 40:25; 46:5]. That’s what makes it unique in the first place! Consequently, theologians have had much more success at saying, ‘The Trinity is not this,’ than positively saying, ‘The Trinity is this.’
Now, while it is true that the doctrine of the Trinity is, by far, more clearly evidenced in the New Testament than in the Old, as the Trinity was revealed “between the Testaments,” in the incarnation of the Son and the outpouring of the Holy Spirit, this does not mean that evidence is lacking in the Old Testament. The following sampling of Scriptures provides a glimpse into the glory of the Trinity that is more fully revealed in the New Testament:
Gen. 1:1-3 “In the beginning, God created the heavens and the earth. The earth was without form and void, and darkness was over the face of the deep. And the Spirit of God was hovering over the face of the waters. And God said, ‘Let there be light,’ and there was light.”
Gen. 1:26-27 “Then God said, ‘Let us make man in our image, after our likeness. And let them have dominion over the fish of the sea and over the birds of the heavens and over the livestock and over all the earth and over every creeping thing that creeps on the earth.’ So God created man in his own image, in the image of God he created him; male and female he created them.”
Ps. 33:6 “By the word of the LORD the heavens were made, and by the breath of his mouth all their host.”
Ps. 45:6-7 “Your throne, O God, is forever and ever. The scepter of your kingdom is a scepter of uprightness; you have loved righteousness and hated wickedness. Therefore God, your God, has anointed you with the oil of gladness beyond your companions.” (cf. Heb. 1:8)
Isa. 63:10-11 “But they rebelled and grieved his Holy Spirit; therefore he turned to be their enemy, and himself fought against them. Then he remembered the days of old, of Moses and his people. Where is he who brought them up out of the sea with the shepherds of his flock? Where is he who put in the midst of them his Holy Spirit….?”
Louis Berkhof comments on this progressive nature of the revelation of the Trinity:
The Old Testament does not contain a full revelation of the trinitarian existence of God, but does contain several indications of it. And this is exactly what might be expected. The Bible never deals with the doctrine of the Trinity as an abstract truth, but reveals the trinitarian life in its various relations as a living reality, to a certain extent in connection with the works of creation and providence, but particularly in relation to the work of redemption. Its most fundamental revelation is a revelation given in facts rather than in words. And this revelation increases in clarity in the measure in which the redemptive work of God is more clearly reveled, as in the incarnation of the Son and the outpouring of the Holy Spirit. And the more the glorious reality of the Trinity stands out in the facts of history, the clearer the statements of the doctrine become. The fuller revelation of the Trinity in the New Testament is due to the fact that the Word became flesh, and that the Holy Spirit took up His abode in the Church.
In other words, the doctrine of the Trinity, due to its primary revelation in facts (historical events), is intricately tied to the progress of redemptive history. As redemptive history progressed, so the clarity by which we may see the Trinity also progressed. It is easily understandable, therefore, as to why the New Testament is more abundant in its teaching on this doctrine. Further, we should keep in mind that the New Testament authors, who were rigorous Jewish monotheists (the belief in one God), apparently had no qualms with this revelation. Robert L. Reymond notes this well, saying, “The New Testament writers—thoroughly ‘Trinitarian’ in their theology—evidently saw no incongruity between their doctrine of God and the monotheism of the Old Testament.”
The following is a compilation of select New Testament Scriptures that serve to support this teaching of the Trinity. Some texts only speak of two Persons within the Trinity, whereas others speak of all three. You will note that these passages present the three Persons of the Trinity as distinct, yet equal in being/nature. Keep in mind that “God” frequently refers to the Father, but there are places where it refers to Jesus (Rom. 9:5; Tit. 2:13; 2 Pet. 1:1). These passages reveal to us the importance of this doctrine in relation to the Christin faith and life (e.g. salvation, baptism, prayer, worship). As you read through these texts, ask yourself these questions: How do the Father, the Son, and the Holy Spirit relate to one another? What are their distinct roles? What aspect of the Christian faith/life does this relate to?
Jn. 1:1-5 “In the beginning was the Word, and the Word was with God, and the Word was God. He was in the beginning with God. All things were made through him, and without him was not any thing made that was made. In him was life, and the life was the light of men. The light shines in the darkness, and the darkness has not overcome it.”
Jn. 1:14, 18 “And the Word became flesh and dwelt among us, and we have seen his glory, glory as of the only Son from the Father, full of grace and truth…. No one has ever seen God; the only God, who is at the Father’s side, he has made him known.
Matt. 28:19 “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.”
Acts 2:33, 36 “Being therefore exalted at the right hand of God, and having received from the Father the promise of the Holy Spirit, he has poured out this that you yourselves are seeing and hearing…. Let all the house of Israel therefore know for certain that God has made him both Lord and Christ [Messiah], this Jesus whom you crucified.”
Rom. 8:1-4 “There is therefore now no condemnation for those who are in Christ Jesus. For the law of the Spirit of life has set you free in Christ Jesus from the law of sin and death. For God has done what the law, weakened by the flesh, could not do. By sending his own Son in the likeness of sinful flesh and for sin, he condemned sin in the flesh. In order that the righteous requirement of the law might be fulfilled in us, who walk not according to the flesh but according to the Spirit.”
Rom. 14:17-18 “For the kingdom of God is not a matter of eating and drinking but of righteousness and peace and joy in the Holy Spirit. Whoever thus serves Christ is acceptable to God and approved by men.”
Rom. 15:30 “I appeal to you, brothers, by our Lord Jesus Christ and by the love of the Spirit, to strive together with me in your prayers to God on my behalf.”
1 Cor. 12:4-6 “Now there are varieties of gifts, but the same Spirit; and there are varieties of service, but the same Lord; and there are varieties of activities, but it is the same God who empowers them all in everyone.”
2 Cor. 13:14 “The grace of the Lord Jesus Christ and the love of God and the fellowship of the Holy Spirit be with you all.”
Gal. 4:6 “And because you are sons, God has sent the Spirit of his Son into our hearts, crying, ‘Abba! Father!’”
Eph. 4:4-6 “There is one body and one Spirit—just s you were called to the one hope that belongs to your call—one Lord, one faith, one baptism, one God and Father of all, who is over all and through all and in all.”
Phil. 3:3 “For we are the [true] circumcision, who worship by the Spirit of God and glory in Christ Jesus and put no confidence in the flesh.”
Col. 1:13-14 “He [the Father] has delivered us from the domain of darkness and transferred us to the kingdom of his beloved Son, in whom we have redemption, the forgiveness of sins.”
1 Thess. 4:7-8 “For God has not called us for impurity, but in holiness. Therefore whoever disregards this, disregards not man but God, who gives his Holy Spirit to you.”
2 Thess. 2:13-14 “But we ought always to give thanks to God for you, brothers beloved by the Lord, because God chose you as the firstfruits to be saved, through the sanctification by the Spirit and belief in the truth. To this he called you through our gospel, so that you may obtain the glory of our Lord Jesus Christ.”
Tit. 3:4-7 “For we ourselves were once foolish, disobedient, led astray, slaves to various passions and pleasures, passing our days in malice and envy, hated by others and hating one another. But when the goodness and loving kindness of God our Savior appeared, he saved us, not because of works done by us in righteousness, but according to his own mercy, by the washing of regeneration and renewal of the Holy Spirit, whom he poured out on us richly through Jesus Christ our savior, so that being justified by his grace we might become heirs according to the hope of eternal life.”
Heb. 1:1-3 “Long ago, at many times and in many ways, God spoke to our fathers by the prophets, but in these last days he has spoken to us by his Son, whom he appointed the heir of all things, through whom also he created the world. He is the radiance of the glory of God and the exact imprint of his nature, and he upholds the universe by the word of his power. After making purification for sins, he sat down at the right hand of the Majesty on high.”
Heb. 9:14 “How much more will the blood of Christ, who through the eternal Spirit offered himself without blemish to God, purify our conscience from dead works to serve the living God.”
1 Pet. 1:2 “[To those who are elect] according to the foreknowledge of God the Father, in the sanctification of the Spirit, for obedience to Jesus Christ and for sprinkling with his blood.”
Hopefully, you have recognized some key areas in the Christian life where the triune relationship of the Father, the Son, and the Holy Spirit play a vital role. Indeed, it is impossible to talk about the Christian faith and life without bringing into the discussion the triune nature of God (whether we realize it or not). So, following are a few summary points based on the above passages in order to drive home the significance of the Trinity in our faith and life.
Salvation: The Father chooses and adopts his people; the Son secures their redemption by his obedient life and substitutionary sacrifice; and the Holy Spirit applies the work of Christ’s redemption to God’s elect in regeneration, sanctification, and the sealing of their eternal inheritance (cf. Eph. 1:3-14).
Worship: Worship and praise is due to the Father, the Son, and the Holy Spirit, although the Scriptures typically present the Father and the Son as the objects of our worship, with the Spirit empowering and moving us in worship. In short, praise and thanks is typically expressed to the Father, through the Son, and in the fellowship and power of the Spirit.
Prayer: We pray to the Father, in the name of Jesus Christ, and in the power and guidance of the Spirit.
What this study has demonstrated is that Christianity is trinitarian through and through. The doctrine of the Trinity is essential to our faith and life. Indeed, it is essential to the core of Christianity, the gospel itself (Eph. 1:3-14). For this reason, and others, we should be thoroughly grounded in and convinced of this most precious and glorious truth regarding the nature of God. Many more Scripture references could have been listed. Hopefully, this study will encourage you to look for such texts and to take note of their theological significance. If you desire to engage in further study on the Trinity, and I think you should, I recommend to you the following three books: 1) The Forgotten Trinity (James White); 2) Delighting in the Trinity (Michael Reeves); and 3) The Holy Trinity (Robert Letham).
“To whom then will you compare me, that I should be like him? says the Holy One.” (Isa. 40:25)
 White, James. The Forgotten Trinity (MN: Bethany House Publishers, 1998), 26.
 Ibid., 29. Emphasis is his.
 A phrase commonly used by James White when discussing the revelation of the Trinity.
 Emphasis added. It has been suggested that the plural is to be understood as a plural of majesty, much like a king may use the plural to refer to himself. It has also been suggested that God’s heavenly angelic court is in view. The problem with this, however, is that it would suggest that the angelic hosts had a role in creation and that we are not only made in God’s image but also in the image of angels, which the Scriptures do not teach. I believe this is an indication of the plurality of Persons in the one God, more fully revealed in the NT.
 Berkhof, Louis. Systematic Theology (MI: Eerdmans Publishing Co., reprinted 1974), 85.
 Reymond, Robert L. A New Systematic Theology of the Christian Faith (TN: Thomas Nelson, 1998), 207.