In the Name of the Father, and of the Son, and of the Holy Spirit. Amen.

Isaiah’s vision of God sitting upon His heavenly throne from Isaiah chapter 6 is the perfect text for us to hear on the Feast of the Holy Trinity, because Isaiah’s vision reminds what God is like and this is the day in Church year when consider God’s properties and His essence. It’s the day when we Christians think more deeply about God Himself. 

The first thing that Isaiah’s vision reminds us of about God is that He is Triune. To be Triune means to be three in one. God is Three in One because even though there is only one God, the Bible teaches us that there are three distinct Persons in the Godhead. The Father is God. The Son is God. And the Holy Spirit is God. And yet, as we say in the Athanasian Creed, there are not three gods, but One God. When the angles sang to one another in Isaiah’s vision, they said, “Holy, Holy, Holy, is the Lord of Hosts; the whole earth is full of His glory.” The angels called the One Lord, “holy,” three times over, because He is thrice holy. He is Three in One. 

Sometimes it’s suggested that the doctrine of the Trinity is not something that comes from the Bible but something that the Church just made up later on. But that’s not true at all. God has revealed Himself as Triune all throughout the Scriptures in both the Old and the New Testaments alike. In addition to what the angels sang in Isaiah vision, there is also, for example, the way that God spoke about Himself at the very beginning of creation. Right before God created Adam and Eve in Genesis chapter one, the Bible tells us that God said, “Let us make man in our image, after our likeness. And let him have dominion over the fish of the sea and over the birds of the heavens and over the livestock and over all the earth. So, God created man in His own image, in the image of God He created him.” Notice how in these verses God refers to Himself in both the singular and the plural. That’s because He is both of those things at the same time. He is Three in One. Likewise, we find another reference to the Trinity in the words of King David from Psalm 110. In fact, if you remember, this is the exact passage that Jesus once used to prove His divinity to the Pharisees. David says, in the Spirit, “The Lordsays to my Lord: ‘Sit at my right hand, until I make your enemies your footstool.’” Here, again, we have a reference to all three Persons of the Holy Trinity. There is David speaking in the Spirit about God the Father talking with God the Son. And all of this comes from the same Old Testament that tells us plainly, “Hear, O Israel: The Lord our God, the Lord is One.”

Besides the many references to the Trinity in the Old Testament, there are also, of course, an overwhelming number of passages about it in the New Testament. There’s Jesus’s Baptism where God the Father speaks from heaven to God the Son while God the Holy Spirit descends in the form of a dove. There are the words of Jesus from John 8 and John 14, where Christ tells us that He is the “I AM” and that whoever has “seen Him has seen the Father.” There’s the Great Commission, where Jesus commands His church to go and make disciples of all nations by baptizing them in God’s Name, the Name of the Father, and of the Son, and of the Holy Spirit. And then there are the letters of Saint Paul in which almost every single one of them either begins or ends with an explicit reference to the Triune God. “The grace of our Lord Jesus Christ,” Paul says, “the love of God, and the communion of the Holy Spirit be with you all.”

The real reason why some people reject the doctrine of Trinity in not because it isn’t found in the Bible, but because it is hard for them to understand. In fact, it’s impossible for us to understand. How can God be Three in One? How can Jesus be God, and the Father be God, and the Holy Spirit be God, and there still only be One God? The answer is, only God knows. One of the things that makes God, God in the first place is the reality that He is beyond our understanding. God knows more than we do, and especially about Himself. If we can’t even understand things like gravity, or time and space, and get overwhelmed when we try think about how those things for too long, then why would we expect to have prefect understanding of the One who made all of those things to begin with? We shouldn’t. We should approach God with humility. We should listen to what God says about Himself in His Word and then we should simply say back to Him the same thing, even if it doesn’t always make perfect sense to us.

The doctrine of the Trinity is not a way to try and explain God, or make sense of God, it is the Biblical way to confess God. We confess God in the way that He tells us to confess Him, because every other thing that someone might say about Him is just another way to deny Him. Whenever a person denies the doctrine of the Trinity, or any other teaching from the Bible for that matter, because it’s beyond their reason, what they are really doing is denying God Himself. They’re putting themselves in the place of God, and worshiping their own brain instead of the One who gave it. They are turning their mind into an idol. But the problem with idols is that they can’t save us. Only God can save us. And as we are reminded from Isaiah’s vision, the real God is Triune. He is Three in One.

The second thing that Isaiah’s vision reminds us of about God is that He is Holy. Besides being Three in One, and each Person of the Trinity being perfectly united with one another other while at the same time perfectly distinct from each other, God the Father, Son, and Holy Spirit, are also altogether perfect in every way imaginable. Again, when the angels sang their song about God in Isaiah’s vision they said, “Holy, Holy, Holy, is the Lord of hosts; the whole earth is full of His glory.” God is Holy in and of Himself because He is without the one thing that makes something unholy. God is without sin. As the Bible says elsewhere, “You are not a God who delights in wickedness; and evil may not dwell with you.” 

Yes, it’s true that when the prophet Isaiah got to look at God in all of His glory, it made him very afraid. But the reason why Isaiah was so terrified was not because there was something wrong with God, but because there was something wrong with him. Isaiah was a sinner.  As Isaiah himself said, “Woe is me! For I am lost; for I am a man of unclean lips, and I dwell in the midst of a people of unclean lips; for my eyes have seen the King, the Lord of hosts!” All throughout the Scriptures, there are examples of sinners coming into contact with God and that encounter bringing them to their knees in humble repentance. What did Saint Peter do when he witnessed the miraculous catch of fish? The moment that Peter realized what had taken place, and who he was standing next to, he fell on his face at Jesus’ feet and said to Him, “Go away from me, Lord; I am a sinful man.”

God’s Word shows us repeatedly that it’s not safe for sinners to stand in the presence of God with their sin. And that’s not because God is not good. It is because His goodness is so good that it cannot tolerate any evil at all. Just like a police officer can be good and dangerous at the same time, because they’re dangerous to those who are breaking the law, that is how it is with God too. That is how it is with the Author of the Law. One of the things that His perfect holiness always does is expose our unholiness. It shows us just how bad our sin really is.

It's become very popular these day for churches to replace Biblical concepts like “sin” with words that don’t sound so accusatory like “brokenness.” Especially among the so-called Evangelicals, you will hear people go on and on about how broken they are or how broken the world is, but what you will rarely, if ever, hear them talk about is who did the breaking. But that is very far away from what Isaiah said about himself, and not nearly enough of what the Bible tells us about ourselves. Who did the breaking? Why is there so much suffering in the world? It is not because of God, and it is not only because of other people. It’s also because of us. And the problem with “brokenness theology” is that it shifts the blame away from us. It allows people not to take accountability for their own sin, which makes it impossible for them to receive forgiveness for it.

The first thing that we Lutherans do in our worship services is have confession and absolution. When we come into God’s House, and approach the throne of His holy altar, before we say anything else, the first thing that we say is that we don’t deserve to be there. The first thing that we do is acknowledge that if God did what was right, that is, if He did what He had every right to do, we wouldn’t be allowed to be there at all. We don’t shift the blame to somebody else. We don’t pretend that there is no one to blame at all. We take the blame ourselves. If we have sin in our lives, we confess it for what it is. If we’ve put things before God and His Word, if we’ve skipped church, been lazy in our prayers or devotional life, dishonored our parents, hurt our neighbor, polluted our bodies, lied, lusted, cheated, or stolen, we admit it. We own up to it and we repent of it. We ask God to take away our sins from us, because if He didn’t do that, then our sins without a doubt condemn us. If God didn’t remove our sins from us, then as Isaiah says, we would all be lost. And again, that is because God is holy.

But the last, and the most important thing, that Isaiah’s vision reminds us of about God, is that He is merciful. Not only is God Triune, and not only is He holy, but above all, He is forgiving. The perfect God wants to be with His imperfect creatures. And since, we cannot stand to be with Him because of our sins, He Himself does what we could never do and takes those sins away. After Isaiah cried out to God in repentance, after he admitted to God who he was, what he had done, and what he deserved to happen to him because he did it, what did God do for Isaiah? God sent one of the seraphim to him, having in his hand a burning coal that he had taken with tongs from the altar. Then the angel touched Isaiah’s mouth and said to him, “Behold, this has touched your lips; your guilt is taken away, and your sin atoned for.”

When we confess our sins to God, God forgives them. He forgives them, because He has already atoned for them. His very own Son paid the price for them all. As we read in Revelation chapter 13, “the Lamb was slain from the creation of the world.” That doesn’t mean that Jesus died on the cross before God made the heavens and the earth, but it does mean that what He did in space and time, counts for everyone no matter what place and time they live in. Isaiah lived long before Jesus was ever born, and you live long after. But the atoning sacrifice of Christ is what makes it possible for us to stand in God’s presence. 

One of my favorite parts of the Lutheran Liturgy, besides the confession of sin, is what we sing right before the pastor says the Words of Institution and we take Communion. I don’t know if you’ve ever made this connection before, but we sing the song of the angles. We sing the same thing that the six-winged seraphim sang from our reading today: “Holy, holy, holy, Lord God of power and might; heaven and earth are full of His glory.” The reason why we sing that song when we do is because it reminds us of how the same thing that happened for Isaiah also happens for us. When Isaiah confessed His sins to God, and humbled himself before the Lord, God provided him with a pledge and promise of His forgivness. When Isaiah admitted that he was a man of unclean lips, who dwelled in the midst of a people of unclean lips too, God sent one of His messengers to take something off the altar and place it on his lips to cleanse him. And what happens for us when we take Holy Communion? God sends one of His messengers to His altar again, to place something on our lips that cleanse us too. He gives us a pastor to bring us the Body and Blood of Jesus, which though it can be like a burning coal for those who take it wrongly, is the assurance of forgivness, life, and salvation, for all those who receive it in faith.

The celebration of the Lord’s Supper is the high point of our worship service. It’s the greatest moment in our life, even though it can happen every week or multiple times a week, because it’s the moment that we come in contact with the Triune God who gives us healing. If you’re weak and ashamed, if you’re disgusted with yourself and your sins, if you’ve done things that make you feel gross, and you wish you’d never done them, but can’t take them back, God has given you a remedy for that. He’s given you the Blood of His Son. Remember what Saint John tells us about the Blood of Christ in 1 John chapter 1. The blood of Jesus His Son,” he says, “cleanses us for all sin.” All sin. The sins you know about. The sins you’ve forgotten. The sins that keep you up at night. And the sins that you just can’t seem to stop doing no matter how hard you try. Through the blood of Jesus, God takes them away. And when you eat His Body and drink His Blood, in faith God cleanses you from them, like He cleansed Isaiah. He makes you fit for His presence and His service, and equips you to live in your vocations with a clean conscience.

Isaiah’s vision of God from Isaiah chapter six reminds us what God is like. He is triune. He is holy. And He is merciful. That’s the way that God has revealed Himself to us in His Word, and so that’s the way that we confess Him before the world. That is what we say about Him even if it means saying things that other people don’t like to hear. The world doesn’t think that it’s very nice to tell the Mormons, the Muslims, the Jehovah’s Witnesses, and the Jews that they aren’t worshiping the true God because all of them deny the Trinity. But we say it anyway, because we know that it’s only the Triune God who can save us. It’s only Jesus who has the power to take away our sin. And He has. So let us worship Him in the Unity of the Divine Majesty, praising God together with the angels, and singing with them, “Holy, Holy, Holy, is the Lord of Hosts; the whole earth is full of His glory.” In Jesus’ Name. Amen.