Trinity Sunday focuses our attention on the doctrine of the Holy Trinity, the distinctive Christian teaching on God. The Athanasian Creed, in which this doctrine was first set forth in detail, declares that no one can be saved unless he believes it. But it places a severe burden on our understanding. It is not easy to believe that God can be one and three at the same time. A contemporary theologian has said of the Trinity, "While one may be in danger of losing his soul by denying it, he is in danger of losing his wits in trying to understand it." We are dealing here with a paradox and a mystery, and the church has always rejected easy ways of trying to solve it. I lectured once on this subject to a group of religious educators, and in the discussion that followed, one teacher said, "I have had no trouble in explaining the Trinity to my class. I use this analogy. Water comes in three forms. It is a liquid, but it may also be congealed matter, as in ice, or a vapor, as in steam. Still it is the same substance. So it is with the God whom we know as Father, Son, and Holy Spirit." I had to reply, "You mean well, but you are guilty of what the early church called ‘the modalistic heresy,’ dealing with the three persons as mere modes or appearances behind which must be some unknown fourth reality of which they are modes." The same applies to other analogies, such as the sun, sunlight, and sunshine. The church teaches that each of the three persons of the Trinity is God himself, not just an appearance of God. God, the Father Almighty, Maker of heaven and earth, is the one and only true God. Jesus Christ, Son of God, Redeemer of the world, is not just the greatest of men, prophet, and martyr, but "very God of very God." The Holy Spirit, the Sanctifier, is God himself dwelling in human hearts. Yet there are not three Gods but one God. How can this be? Our ordinary arithmetic cannot figure it out. Saint Augustine, one of the greatest intellectual giants of all time, wrestled with this problem for days. Finally he had a vision in which he saw a little boy filling a pail with water from the ocean, carrying it some distance, and then dumping it in another place. "What are you doing, little boy?" asked Augustine. "I am moving the ocean from this place to that place," said the boy. "You foolish lad," said Augustine, "you cannot empty the ocean with your little pail." "You call me foolish," replied the boy, "but what about you? Do you think that with your human mind you will succeed in encompassing the mind of God and emptying the depths of the Trinity?" Augustine awoke and concluded: The only way to think of the Trinity is to think of the unfathomable love of God which unites creation and redemption and is made real to us through the Holy Spirit. When the Holy Spirit has led us into the presence of the God who reveals himself in Christ, then our only adequate response is the awe of worship and the commitment of faith. We say with the apostle, "O the depth of the riches and wisdom and knowledge of God! How unsearchable are his judgments and how inscrutable his ways!" (Romans 11:33). We join the worship of the church through the ages, "We laud and magnify thy glorious Name; evermore praising thee, and saying: Holy, holy, holy, Lord God of Sabaoth, heaven and earth are full of thy glory." And we respond with our whole lives, "Love so amazing, so divine, demands my soul, my life, my all." But when instead of worship and commitment we seek an intellectual interpretation of the meaning of this revelation of God, we are on the road that leads inevitably to the doctrine of the Trinity. That is precisely what happened to the early church. The Bible has no such explicit doctrine and no such word. There is no basis for it in the Old Testament unless one reads Christian theology into it. The faith of Judaism was and continues to be simple monotheism: "Hear, O Israel, the Lord our God is one God" (Deuteronomy 6:14). Yet against the background of this strict adherence to the one God and in full accord with it, rose the apostolic Christian community with its new living contact with God in Christ. The first Christians confessed, "Jesus is Lord," and they lived by the gifts of his Spirit. They constituted a fellowship of the Spirit which their Lord Jesus Christ had given them after returning to the Father who had sent him. Thus they had implicit faith in the Trinity, although there was no need as yet to think it through or to coin a word for the conclusion. In this faith they would encourage one another, for example, to "be filled with the Spirit ... always and for everything giving thanks in the name of our Lord Jesus Christ to God the Father" (Ephesians 5:18-20). The Trinitarian faith of the church of the New Testament finds its clearest expression in the two passages selected as the text for this sermon. In the "great commission," often called the charter by which the church operates, the Lord gives his church the mandate to make disciples of all nations, "baptizing them in the name of the Father and of the Son and of the Holy Spirit." The three persons of the Trinity are mentioned in the order in which the church was later to formulate the doctrine, and it is significant that baptism was to be in the name, not names, of the one God. It is also significant that in the apostolic benediction, which likewise refers to the three persons, the order is changed. "The grace of the Lord Jesus Christ" is first. While these texts became important in the development of the doctrine of the Trinity, the doctrine itself does not rest on any specific isolated passages of scripture but on the content of the Christian revelation as a whole. It is the entire gospel in a nutshell. As such it is the specific Christian concept of God. Although the apostles did not raise the question of how God could be both one and three, once the question was raised, the church could be true to itself only by replying in terms of the Trinity. It is the only answer which does justice both to the centrality of Christ and to the continuing reality of the presence of Christ. The Trinity is, first of all, an affirmation of the centrality of Christ in the faith of the church. Worship of the one God whom Jesus worshiped and whom he revealed as "Father" is of course self-evident. But as the apostolic benediction implies, the key-member of the Trinity is the Second Person. The Father is "the Father of our Lord Jesus Christ," the grace of God is "the grace of the Lord Jesus Christ," and the Holy Spirit does not speak of himself but of Christ. Had the church not felt constrained to assert emphatically that Christ is nothing less than "very God of very God," there would have been no need for the doctrine of the Trinity. Greek antiquity was familiar with various "sons of God," men who were regarded as having achieved the rank of deity or at least of demi-god. A man such as the physician Aesculapius, for example, was thought to have actualized the divine potential in human nature and became the god of healing. But when this line of thinking was applied to him whom the church worshiped as Lord, "in whom dwelt all the fullness of the godhead bodily," it was infuriatingly inadequate. The 318 church fathers assembled at Nicea, who declared Christ to be "very God of very God," could not help literally tearing to pieces an Arian confession written in such vein. To the church, Christ was no demi-god or a deification of man but the very incarnation of God, the Word become flesh. It was because the center of its faith, "God in Christ," was challenged, that the church was led to formulate the doctrine of the Trinity. Even today this doctrine is of fundamental importance only to a thoroughly Christ-centered theology. The "great commission" makes clear that the divine sovereignty of Christ is the basis of the mission of the church. "All authority in heaven and earth has been given to me," says the risen Christ. He is the ruler of life, the determiner of destiny. His authority extends over everything in heaven and earth. It is not confined to the church but encompasses the entire universe. It applies to every action and every decision we make. What we proclaim, said Paul, "was not done in a corner." The cross of Christ is planted in the center of all existence. "God was in Christ reconciling the world to himself" (2 Corinthians 5:19). This redemptive act means that the world belongs to Christ. He will not give up anything that he has won. He will not be satisfied with ruling over only a segment of the world or a portion of your life. Christians are people who acknowledge the authority of Christ, who "crown him Lord of all," who obey what he commands. And his last great command is: "Go and make disciples of all nations." Make known my redemptive power to all people everywhere, bring every area of life under my sovereignty. This mission, empowered by his own presence, goes on "to the close of the age." When the curtain is lifted on the last scene of human history, every knee will bow and every tongue will confess: "Jesus is Lord." The doctrine of the Trinity gives expression not only to the centrality and sovereignty of Christ but also to the continuing reality of his presence. Had the manifestation of God in Christ been only an historical event, apprehended directly only by a few who were privileged to know Jesus during his life on earth, there would have been no need for a third Person of the Trinity. The true divinity of the Holy Spirit is the church’s witness to the living and abiding reality of the Christ-revealed God. Through the Holy Spirit Christ fulfills his promise, "I am with you always." He continues to be present among his people and to afford them person-to-person experience of God and not mere knowledge about God. Giver of life and power, the Spirit reveals "God in Christ" at work in the hearts of men. Thus he makes possible a genuine and vital witnessing on the part of the church. He leads individual men and women into personal faith in Christ but he also binds believers together into "the fellowship of the Spirit." The Trinity, then, is the church’s interpretation, in the language of an ancient day, of the living contact with God which Christ gives us. Instead of speaking about one substance and three persons, we could say in today’s language: The Trinity is the revelation of God, given in Christ, and continuing to operate in the Holy Spirit. God is one, not in the sense of barren arithmetic but in a higher and richer threefold sense in which God remains the one true God even though he reveals himself to us in Christ and continues to communicate himself to us in the Holy Spirit. God so loved the world that he gave his only Son, the Son of God is our Lord and Redeemer, and the Holy Spirit makes redemption real in our experience. This kind of logic can be grasped only from the center of the gospel: God is love. Augustine was right, "You have an insight into Trinity, if you have an insight into love." Just as love is the last word about God, so Trinity is the last word in the doctrine of God. The doctrine of the Trinity, as the Athanasian Creed holds, shows a Christian how he is to think about God. The church clings to this way of thinking because no acceptable substitute has been offered. But any thinking about God is a poor substitute for confronting God himself. The Trinity becomes meaningful to us only when the Spirit operating in the Christian fellowship leads us to acknowledge in personal living faith: "Jesus is Lord."