Grace to you and peace from God our Father and the Lord Jesus Christ. Amen.
1. Today we celebrate the Feast of the Holy Trinity. This feast day is actually one of the newest feast days in the church year. It didn’t come into widespread use in the church until the 11th century. This feast day is unique in that it is the only day of the church year dedicated to a doctrine rather than a person or event in the life of our Lord or of the church. And believe it or not, it was actually the clergy who resisted a special celebration dedicated to the Holy Trinity, insisting that every day in the church is Trinitarian. The laity felt strongly, however, that a day dedicated to the doctrine of the Holy Trinity was important. And so, thankfully, the laity prevailed, and so here we are. Now, the clergy who resisted were right in that every part of our life together in the church is Trinitarian. But the importance of this day is that it offers us an opportunity to celebrate and appreciate the doctrine of the Holy Trinity more fully than we often do.
2. Contrary to many non-Christian accusations, the doctrine of the Holy Trinity was not made-up by some church council or group. Yes, the word Trinity was coined by the church, but the doctrine itself is very Scriptural. The doctrine of the Holy Trinity, as we confess it, is essentially an exposition on Matthew 28:19, when our Lord said to his disciples: “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” (Matthew 28:19). It is the last part of the verse that is of particular relevance: “In the name of the Father and of the Son and of the Holy Spirit.” There is a singular name, or a singular essence, shared by three distinct persons: Father, Son, and Holy Spirit. The entire Athanasian Creed is a further unpacking of this unity of essence and distinction of persons.
3. So, it’s fitting that this Feast of the Holy Trinity has in many ways become synonymous with the Athanasian Creed. The Athanasian Creed itself has two parts. The first part deals with the relationship of the Father, Son, and Holy Spirit. The second part deals with the two natures in Christ. When many of us think about the Athanasian Creed, we tend to think most about the first part. We think about how it’s so long and repetitive. And it is. But long and repetitive isn’t necessarily bad. Length and repetition are important teaching tools. The Athanasian Creed begins: Whoever desires to be saved must, above all, hold the catholic faith. Whoever does not keep it whole and undefiled will without doubt perish eternally. And the catholic faith is this, that we worship one God in Trinity and Trinity in Unity, neither confusing the persons, nor dividing the substance. And then we get the long, repetitive list, which begins with: For the Father is one person, the Son is another, and the Holy Spirit is another… And then it goes on to painstakingly articulate the distinction of the persons and the unity of the substance. This is the part of the Athanasian Creed that we tend to think most about, as it teaches us about the mystery of the Holy Trinity with the goal that we may worship our Triune God rightly.
4. But the second major section of the Athanasian Creed deals with the two natures in Christ, which is closely related to the doctrine of the Holy Trinity. The doctrine of the two natures in Christ is essentially a further articulation of one word in that verse from Matthew 28:19. It’s an articulation of the word “Son.” What does it mean for the second person of the Holy Trinity to be “the Son”? Indeed, who is the Son? To answer this question, I would like to draw your attention to two statements that our Lord Jesus makes about himself in our Gospel Reading for today, which affirm the teaching articulated in the second half of the Athanasian Creed.
5. The first is in verses 13 and 14 when our Lord refers to himself as “the Son of Man.” In the Hebrew idiom, to call yourself “the son of something” was to say, “I am that thing.” For example, when the people of God in the Old Testament are called “the sons of Israel”, or “the children of Israel” as it’s often translated in our Bibles, that’s the same as calling them Israelites. That’s why we use those terms synonymously. So, when our Lord calls himself, “the Son of Man,” he is saying, “I am man.” As you may know, the Hebrew word of “man” is “adam.” Our Lord Jesus is not only “the son of Adam”, he is the new Adam—the new and perfect human who has come to earth to be fully human as our ancestor Adam, and indeed all of us, are unable to do. Jesus is the fully human one who lived in complete obedience to the Father, as we have been called to, but haven’t done.
6. But notice what our Lord says about himself in verses 14 & 15: “And as Moses lifted up the serpent in the wilderness, so must the Son of Man be lifted up, that whoever believes in him may have eternal life.” When the Israelites sinned in the wilderness and failed to live in complete obedience to the Father, he sent venomous snakes to punish them. But he also provided a way of rescue. He commanded Moses to make an image of a serpent and lift it up so that whoever looked upon it would be saved. In a similar way, our Lord Jesus was made to be like us in every way. And by “in every way” I mean every way except that he was without sin. He was fully man—complete with a body, mind, and spirit. He wasn’t just some shell of a man or body inhabited by God. No, he was and still remains fully man. And so, when the man Jesus was lifted up on the cross, it was for the purpose of our salvation so that when we look on him and believe, we too are saved.
7. But notice too that Jesus isn’t only the Son of Man, he is also the Son of God. That is to say, he is God. He is fully man and fully God. His human nature does not somehow taint or compromise his divine nature. He is and ever remains the unchangeable Son of God. And so, when the second person of the Holy Trinity was joined to our human nature in the person of Jesus, God didn’t change. God is immutable, which means he never changes. God didn’t change when he was joined to our human nature in Jesus. Rather, humanity changed—and for the better. In the person of Jesus, the divine attributes of God were communicated to the human nature at various moments. This is how our Lord was able to walk on water or change water into wine. But the fact that the divine attributes were communicated to the human nature at times does not make the reverse true. The attributes of the humanity were not communicated to the divinity. God remains God. He has not changed. What has changed is humanity, which has been joined forever to God in the person of Jesus.
8. But notice why this is significant. Again, it’s all about our salvation. You know the verse: For God so loved the world, that he gave his only Son, that whoever believes in him should not perish but have eternal life (John 3:16). The Son of God came to earth to earn our salvation. The Son of God came to be lifted up on the cross so that you might look upon him and be saved. It is the Son of God—God himself—who did this. That’s why we rightly confess on Good Friday and Holy Saturday: “Oh sorrow dread! Our God is dead, Upon the cross extended, There His love enlivened us As His life was ended (LSB 448:2). We’re not Nestorian heretics who believe that the divine and human natures in Christ were separated on the cross. In Jesus, God died for us on the cross. And because God died for us in Jesus, the sacrifice of his full humanity, which had been joined to the divine nature, was acceptable to the Father. And because full atonement was made for our sins, our Lord Jesus was granted a new life, which is also ours in Baptism. For God said not send his Son into the world to condemn the world, but in order that the world might be saved through him (John 3:17). Thanks be to God that our Triune God acted definitively for us men and for our salvation in the person of Jesus. May God grant us grace to respond to him in worship and praise for this and for all his many blessings to us.
In the name of Jesus. Amen.