Summary: The Trinity allows fellowship within the Godhead, and allows men to enter into real fellowship with God.

What’s today? Fathers Day.

This is Trinity Sunday. Today is the great patronal feast day of our Cathedral. And we of the Missionary Diocese of All Saints, we all share a common life, and we get to celebrate this feast day together because, in the diocese, we are one church. Isn’t that splendid? And this is the only Sunday on which any clergyman dares broach one topic—the most obscure of doctrines—the Trinity.

Now—and please be honest with me—do you think that the belief, the doctrine, the dogma, that God is Trinity really affects your life? How can something so difficult to understand, so remarkably strange and out there, really matter to me down here? Well, I’m going to tell you! Because God is Trinity, we have the opportunity to fellowship with Him. If He were otherwise, we could not.

Trinity is absolutely essential to the Christian faith. You cannot rightly bear the name Christian and deny the Trinity. Our forebears, our fathers and mothers in the faith, fought to protect this belief—they went into exile in foreign lands, suffered persecution at home, and even martyrdom—rather than allow it to become diluted with irrelevant matters or tainted with untruth. These saints who preserved the Faith, our Faith, your faith and mine, invested their lives into upholding a right view of the Trinity.

It’s only right, then, that we too be ready to defend and pass on whole and intact our Faith. We’re going to use some small terms (just five letters long) and some welterweight ideas (this is basic arithmetic). So I’m not going to talk down to anyone or candy-coat things.

Let’s talk about one. One plus…nothing…equals? One. One is singular, unity, simplicity, completeness, entirety, rationality. Okay, so do we understand one?

One plus one plus one equals? Three. Three is not singular, complementarity, complexity, harmony, cooperation, completeness. Three is—duh—more than one. So do we understand three better?

What is Trinity? This will be the only really heavy—as in difficult—part that we’ll go over. I promise it will be short. Can you hang with me for a minute and a half? I think you can. Trinity is Tri-unity. Three in one. The doctrine of the Trinity says that God is three persons (ὑpόstaseς) in one being (oὔsioς); three existences in one essence. The Father and the Son and the Holy Spirit are not three gods, but One God.

Trinity also means that God is One in three. God’s one essence, His essential being, the What of God, is expressed in the Father, Son, and Holy Spirit, the Who of God. The three are not the same who but are the same what. The Father and the Son are distinct persons and they exist without confusion as God, but they are united in the Godhead; they do not have a different god-ness, but are one. Is your head spinning? Well, we’re done with the hard stuff; it’s all downhill from here.

At His essence, God must be one. “Hear, O Israel, the LORD your God, the LORD is one” (Dt. 6:4). God is one. He is not duplicitous—He “does not change like shifting shadows” (Jas. 1:17). He is singularly God; there is no God but Him “I am the LORD; that is my name! I will not give my glory to another or my praise to idols” (Is. 42:8). He alone is Holy. “Holy, Holy, Holy is the LORD God Almighty!” (Is. 6:3). God alone is mighty to perform His works. “Who among the gods is like you, O LORD? Who is like you—majestic in holiness, awesome in glory, working wonders?” (Ex. 15:11). There is no other god like our God, the LORD! He is One.

In His persons, God is three. The Father is God; the Son is God; and the Spirit is God. But the Father is not the Son or the Spirit; the Son is not the Father or the Spirit; and the Spirit is not the Father or the Son. Each has their own person-hood, but they are all one and the same nature—essence. God the Father is the Creator, the Begetter, and the Source. God the Son is the Redeemer, the Begotten, the Word, and our Brother. God the Spirit is the Sanctifier, He Who proceeds, the Paraclete, Helper, and Advocate.

Now with this brief discussion, do we understand, comprehend, the Trinity? Certainly not! But I’d like to move from discussing what the Trinity is, and skip over the question how God is Trinity, because it’s really simple. No, really, it is. It’s a mystery!

So let’s continue, because I really want to discuss a little about why God is Trinity. Did you ever think about why God isn’t just one, and that’s all? Or why he can’t just be three-in-three. If you ever doubt that God doesn’t contain the perfection not just of masculinity, but also of femininity, the complexity of the Trinity should assure us—why are ladies so complicated? Actually, it’s not correct to call God complex, but that’s another sermon.

Why is God a Trinity? This is where Trinity Sunday really gets exciting, because it involves you and me and our everyday lives with Him and our lives with each other. Doesn’t that sound intriguing? Let’s dig in.

If God were a monad—that is just one person, one unit, an indivisible and simple entity—He would be utterly alone. He wouldn’t be lonely. God is perfect, containing within Himself everything He needs and everything He wants. God has no need for creation; whether we’re here or not, He is God. (Not so for us: if God doesn’t exist, then we surely don’t exist either.) If God were one person, all of His perfection would be locked up tightly within Himself—free to act or not act, but never finding fellowship or union. Now there is a sense that God (Father, Son, and Spirit together) is a monad, as He alone is God…more three-in-one stuff…

If God were a dyad—that is two persons, a two-part unit, like a song, with both words and music, or a hamburger with both beef and bun—He would no longer be alone, but He would have union entirely within His own two persons. Again, recall that God is perfect and self-sufficient. If there were, say, just a father and just a son, the two would be always focused on each other; their gaze would never depart from one another, and their union would be confined to this one-dimensional relationship. The other (bigger) problem with the idea of God as a dyad is that the number two implies opposition—heads and tails, white and black, come-heres and from-heres. God cannot be in opposition to Himself. If this dyad were not opposed, then they would be complementary, and the need of distinction in the pair would be lost. And so we reject this view of God.

But…if God is a triad—more than that, a trinity, three persons in one nature, a unit of three, like a musical chord with three notes that work together but form a single whole—He has in Himself relationship and fellowship. Having three persons allows God to be diverse without opposition; where a dyad has two extremes, a triad allows distinction of parts with unity of purpose. God, within the Trinity, is perfect and self-fulfilled, but He is so with relationship. The Father can’t just be with the Son and leave the Spirit in the cold; all three persons are in unity and communion with one another.

And here’s what’s so exciting, what’s so unique about the Christian Faith. Since God is Trinity and since He has relationship and fellowship within Himself, we have the opportunity to share in God’s life. Where one person is exclusive, and two persons make a closed community, three create an open community, true fellowship. You can, as St. Peter wrote, “participate in the divine nature,” because God Himself allows it. There is no god like our God! Can you believe that you and I have the chance to fellowship with God? That is what’s so remarkable about the Trinity. That is good news, saints! We can fellowship with God, just because of the Trinity.

We live in a world that values compromise, tolerance, give-and-take, far more than absolute truth. But God warns us, lest we fall into this trap: “Jacob I loved, but Esau I hated” (Rom. 9:13). Why did God hate Esau? The writer of Hebrews tells us: “…for a single meal [Esau] sold his inheritance rights as the oldest son” (Heb. 12:16). Esau had the inheritance, the birthright, the blessing of his father Isaac, which was the rights to the covenant that God made with Abraham. Esau esteemed little the promise of God, “I am your shield, your very great reward,” and the promise to become God’s own nation. Jacob, however, sought fervently this covenant. Esau was willing to compromise, to sell out his inheritance for a mess of pottage. Perhaps he thought that Isaac would still grant him the blessing, tolerating his verbal denunciation of the birthright. But no! Even with tears and wailing, it would not be so (cf. Gen. 27:33–40). “Afterward, as you know, when he wanted to inherit this blessing, he was rejected. He could bring about no change of mind, though he sought the blessing with tears” (Heb. 12:17). If we think that we can deny the true Faith—in part or in whole—and still hold on to the hope of eternal life—all the good things promised unto them that believe—we deceive ourselves. The revelation that we have received is from God Himself. “No prophecy of Scripture came about by the prophet’s own interpretation. For prophecy never had its origin in the will of man, but men spoke from God as they were carried along by the Holy Spirit” (2 Pe. 1:20,21).

We have a duty, responsibility to pass on to our children, grandchildren, nephews and nieces the Faith once delivered. Do you want to have a legacy? Give them the Faith, untainted by corruptions, in all of its richness, full of life and not languishing, strong and powerful, pointing to the hope we have—eternal life in communion and fellowship with the triune God.