Sermon For Trinity Sunday Year C

One Name, Three Persons, One Mission

The eleventh chapter of Job contains a question that has never been fully answered by any human mind. Zophar asks it plainly: "Can you fathom the depths of God or discover the limits of the Almighty?" The honest answer, of course, is no. And yet here we are on Trinity Sunday, the one day in the Christian year when the Church does not merely encounter a story or a season but is invited to stand before the mystery of who God is. Not what God has done, though that is glorious. Not where God is going, though that is certain. But who God is, in the innermost life of the divine being.

That is either the most intimidating subject a preacher can address, or it is the most liberating one. I believe it is liberating, because the doctrine of the Trinity is not a theological puzzle invented to confuse the faithful. It is the Church's best and most faithful attempt to say what the Scriptures themselves say: that the God who saves us, the God who loves us, and the God who dwells within us is one God, and that this one God is Father, Son, and Holy Spirit.

Let us say it plainly at the outset, so that everything else we explore today has a center to return to. The doctrine of the Trinity is this: there is one God, eternally existing in three distinct persons, Father, Son, and Holy Spirit, each fully God, each distinct from the others, and yet one in being, will, and love. That is the claim. Now let us see why it matters, where it comes from, what it does not mean, and how it changes the way we live and worship.

The Foundation In Scripture

Our Gospel reading this morning places us at the end of Matthew, at what we call the Great Commission. The risen Lord gathers his disciples on a mountain in Galilee, and he speaks with an authority that belongs to no mere teacher or prophet. He says, "All authority has been given to me in heaven and on earth." Then he sends them out with these words: "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."

Notice that word name. Not names, plural. One name. The Father, the Son, and the Holy Spirit share a single name, a single identity, a single divine authority. Jesus does not say baptize them in three names, as though the disciples were being commissioned by a committee. He says one name, and then he unfolds that name as a threefold reality. This is not a formula invented by the early Church centuries later. It is the risen Lord himself, speaking before his ascension, revealing the shape of the God in whose name his people are gathered and sent.

Then hear the closing words of Paul's second letter to the Corinthians, which we read this morning as well. "The grace of the Lord Jesus Christ, and the love of God, and the fellowship of the Holy Spirit be with you all." This is the earliest and most beloved Trinitarian blessing in the New Testament. Paul does not write it as a theological treatise. He writes it as a benediction, a sending prayer over a struggling congregation in Corinth. And in that simple blessing, the whole doctrine is present. Grace belongs to the Son. Love belongs to the Father. Fellowship, communion, participation in the divine life, belongs to the Spirit.

These two texts together, the Great Commission and the apostolic blessing, give us the doctrinal foundation. The Trinity is not a later invention. It is present in the earliest layers of Christian worship, mission, and prayer.

Clarifying The Mystery

Now let us address what the doctrine does not mean, because misunderstanding here is common and the stakes are high.

The Trinity does not mean that God is one person who wears three different masks at different times, sometimes appearing as Father, sometimes as Son, sometimes as Spirit. That error has a name in the history of the Church. It is called modalism, and it collapses the real distinctions between the persons. When Jesus prays to the Father in the Garden of Gethsemane, he is not talking to himself. When the Spirit descends upon Jesus at his baptism and the Father's voice speaks from heaven, three distinct persons are present and active in the same moment.

Nor does the Trinity mean that there are three separate gods, each with their own domain and authority. That is tritheism, and it contradicts the clear testimony of Scripture from beginning to end that the Lord our God is one.

The orthodox understanding, the one the Church has held from the councils of Nicaea and Constantinople through the Anglican formularies and the Book of Common Prayer, is that there is one divine being, one God, in whom three persons are co-equal, co-eternal, and distinct. The Father is not the Son. The Son is not the Spirit. The Spirit is not the Father. And yet they are not three gods but one God.

An analogy will only take us so far, and we should be honest about that. No earthly image fully captures the mystery. But consider this much: love, by its very nature, requires more than one person. Love is relational. And if God is love, as John tells us, then the Trinity reveals that love is not something God decided to do when he created us. Love is what God is, eternally, within the life of the Father, Son, and Holy Spirit. Before the first star was formed, before the first breath was drawn, there was already love. There was already communion. There was already the giving and receiving of grace within the life of God.

That is not a cold philosophical claim. That is the most warming truth in all of Christian theology.

The Three Gifts And What They Mean For Us

Return to Paul's benediction. "The grace of the Lord Jesus Christ, and the love of God, and the fellowship of the Holy Spirit be with you all."

The grace of the Lord Jesus Christ. Grace is unmerited favor, but it is more than that. Grace is the Son of God taking on human flesh, living the life we could not live, dying the death we deserved, and rising so that death itself would not have the final word. Grace is not a feeling. Grace is a person. It is Jesus, who stands at the right hand of the Father even now, interceding for us. When Paul prays that this grace would be with the Corinthians, he is praying that the living Christ would be present among them, not merely his memory, but his ongoing, active, saving presence.

The love of God. This is the love of the Father, the love that sent the Son in the first place. John 3:16 is so familiar that we sometimes stop hearing it. But read it again slowly. God so loved the world that he gave his only Son. The love of God is not a sentiment. It is a decision, a costly one, made before the foundation of the world, to pursue a creation that would wander from him. This love does not wait for us to become worthy. It moves toward us in our unworthiness. It is the love of a Father who sees his prodigal son still far off and runs to meet him.

The fellowship of the Holy Spirit. The Greek word here is koinonia, which means participation, sharing, communion. The Spirit does not merely observe us from a distance. The Spirit dwells within us, prays within us when we do not know how to pray, seals us as God's own, and binds us to one another in the body of Christ. The fellowship of the Spirit is what makes the Church more than an organization. It is what makes the Church a living community, a people who share not just a common belief but a common life in God.

These three gifts, grace, love, and fellowship, are not three separate deliveries from three separate sources. They are the one life of the one God, given to us in three distinct and irreplaceable ways.

The Mission That Flows From The Mystery

Now return to the Great Commission. Jesus does not simply reveal the name of the Trinity as a piece of theological information. He reveals it in the context of sending. "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, teaching them to observe everything I have commanded you."

The Trinity is not a doctrine to be stored in a creed and left undisturbed. It is a doctrine that sends us. Because God is love within himself, he is love toward the world. Because the Father sent the Son, and the Son sends us, and the Spirit empowers the sending, mission is not an optional program of the Church. It is the shape of the Church's life, flowing directly from the shape of God's life.

We baptize in the Trinitarian name because baptism is not merely an initiation rite. It is an adoption into the life of God himself. Every person baptized in the name of the Father and of the Son and of the Holy Spirit is being drawn into the same communion that has existed eternally within the Godhead. That is an astonishing claim. And it is the claim the Church has made every time water has been poured and that name has been spoken.

The Response Trinity Sunday Calls For

So what does Trinity Sunday ask of us? It asks three things, and they correspond to the three persons.

It asks for trust in the grace of the Son. Not trust in our own spiritual performance, not trust in our theological precision, but trust in the one who said, "I am with you always, to the end of the age." Whatever you are carrying this week, the risen Christ is not absent from it.

It asks for rest in the love of the Father. The love of God is not conditional on your consistency. It is grounded in who God is, not in what you have managed to do. You are not loved because you are lovable. You are loved because God is love.

And it asks for openness to the fellowship of the Spirit. The Spirit is not given to isolated individuals alone. The Spirit creates community, binds the broken together, and makes the Church a foretaste of the communion of the Trinity itself.

We will shortly come to this Table, where the grace of Christ is given, the love of the Father is remembered, and the fellowship of the Spirit is renewed. The Eucharist is, in a profound sense, a Trinitarian act. We come not merely to remember a meal but to participate in the life of the God who is himself a communion of love.

Knowing the Trinity is not the finish line. It is the beginning of a life lived in wonder, in trust, and in the mission of a God who has never stopped loving the world he made.

Go, then, in the name of the Father, and of the Son, and of the Holy Spirit.

Sources Consulted

The Holy Bible, Christian Standard Bible. Nashville: Holman Bible Publishers, 2017. Matthew 28:16-20; 2 Corinthians 13:13.

The Book of Common Prayer. New York: Church Publishing, 1979. Baptismal Covenant and Eucharistic Prayers.

Athanasius of Alexandria. On the Incarnation. Translated by a Religious of C.S.M.V. Crestwood, NY: St. Vladimir's Seminary Press, 1993.

Augustine of Hippo. The Trinity. Translated by Edmund Hill, O.P. Brooklyn: New City Press, 1991.

Alister E. McGrath. Christian Theology: An Introduction. 5th ed. Oxford: Wiley-Blackwell, 2011. Chapter on the doctrine of the Trinity.

N. T. Wright. Matthew for Everyone, Part Two. Louisville: Westminster John Knox Press, 2004. Commentary on Matthew 28.