The Holy Trinity
June 3, 2012
Text: Isaiah 6:1-8
Isaiah trembles in the presence of the Lord seated upon His throne, “high and lifted up” (Is. 6:1; ESV). “Holy, holy, holy is the LORD of hosts,” calls one six-winged seraph to another; “the whole earth is full of his glory!” (v. 3). And there is Isaiah, finite human, poor, miserable sinner, exposed in the presence of the thrice-holy God. Holy, Holy, Holy, Father, Son, and Holy Spirit, three Persons, one God, in His majesty. Sin cannot come into the presence of this holiness. Isaiah is a sinner. A sinner cannot see God and live. Isaiah trembles for his very life. “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!” (v. 5). “man shall not see me and live,” God told Moses several hundred years before (Ex. 33:20). That’s the rule. Yet Isaiah lives. What makes the difference? How is that this sinner is allowed to stand in the presence of Almighty God, the Holy One, and live, and even be sent out to preach? An angel, one of the seraphim, took a burning coal with tongs from the altar of God, probably the altar of incense, and he touched Isaiah’s lips with the coal. “Behold, this has touched your lips; your guilt is taken away, and your sin atoned for” (Is. 6:7). The sacrifice of Jesus Christ on the cross, which Isaiah would prophesy with stunning clarity in his 53rd Chapter, has made atonement for Isaiah’s sins and the sins of the whole world, including your sin, beloved. The sacrifice of Jesus Christ on the cross is the sacrifice to which all the Old Testament sacrifices pointed. They were pictures of the once for all sacrifice of the Savior on Golgotha. Here a coal is taken from the Old Testament altar of incense, and the seraph touches it to Isaiah’s lips. The prophet’s lips are purified by fire. He lives because of the atonement of Jesus Christ. He speaks because his lips have been touched with the coal from the altar. The holiness of God consumes Isaiah’s sin. Isaiah is sanctified, made holy by God with God’s own holiness. Forgiven and cleansed, Isaiah is sent out to preach.
God is holy. He is sinless, and hating sin. He is pure. He is the very standard of what it means to be holy. Holiness is defined by His essence. To sin is to fall short of the mark of God’s holiness. That is why none of us can stand before God on our own merit. No matter how good we may be by human standards, we never measure up to God. Even the sinless holy angels, the seraphim in our text, cover their eyes and their feet in the presence of God’s glorious holiness. Sinful humans don’t stand a chance. Unless God does something about it. We’re all undone, as Isaiah confesses, when we come into the presence of the holy God, unless God does something to solve our deadly predicament. And He does. He forgives our sins. He forgives, and He cleanses. He sends Jesus to be the sacrifice for our sins on the cross. He baptizes us into His thrice-holy Name, Father, Son, and Holy Spirit, washing all our sins away. And He touches our lips with something spectacular from the altar, the very body and blood of Jesus Christ, the crucified and risen Son of God.
The Trinity is a ponderous mystery. Who can begin to speak of it? Is it not presumptuous for us sinners to speak about the very essence of the holy God? To be sure, it would be the height of presumption to think we understand, or even begin to comprehend, the mystery of God’s tri-unity. How can 1 Person + 1 Person + 1 Person = 1 God? They mystery of the Trinity defies mathematical equation. If you think you understand the Trinity, how God can be Three in One and One in Three, guaranteed, you’ve got it wrong, friend. Disastrous heresy has resulted from those who think they can understand the Trinity; for example, the Arians, who said that really only the Father is God, and that Jesus is a god, but not of the same substance as the Father. Or the Modalists, who said that God was only one person who appeared in three different masks, the Father in the Old Testament, the Son in the Gospels, and the Holy Spirit ever since. The Arians preserved the three Persons of God, but denied the unity. The Modalists preserved the unity of God, but denied the three Persons. These are heresies, false teachings about God’s essence, that resulted from human beings believing they were capable of comprehending God. God has not given us to comprehend His essence. We sinners think God owes us an explanation about anything and everything we want to know. The truth is, He owes us nothing. What He gives us, He gives us by grace, without our merit or worthiness. He gives it as an undeserved gift. And it’s okay that He doesn’t give us to understand everything. It’s okay that He doesn’t give us to comprehend the mystery of the Holy Trinity. It is enough that He has given Himself to us to believe in and trust. And He has revealed Himself in Christ and in the Holy Scriptures as our God, who loves us, and wants to have eternal communion with us.
And on the basis of His revelation in Christ and in Holy Scripture, there are things that we can know about God. In Christ, we know Him to be the God who saves. We know Him to be a God of love who provides for our forgiveness and salvation: “For God so loved the world, that he gave his only begotten Son, that whosoever believeth in him should not perish, but have everlasting life” (John 3:16; KJV). We know Him to be a self-giving God, for our Lord Jesus was “delivered up according to the definite plan and foreknowledge of God” (Acts 2:23; ESV) to be crucified for our sins, and raised up for our eternal life. And from the Scriptures we know many of God’s works and attributes. God is the Creator of all. He is eternal, unchangeable, almighty (omnipotent), all-knowing (omniscient), present everywhere (omnipresent), holy, just, faithful, good, merciful, gracious. He is all of these and more. God is love (1 John 4:8). He is the God who loves us. He created us. He redeemed us. He sanctifies us and keeps us in the one true faith of Jesus Christ. And yet, having said all of these things about God on the basis of His Word, we cannot say that we in any way comprehend Him. He is incomprehensible. He is beyond our finite understanding. We are not given to understand Him. But we are given to confess Him, and to praise Him.
Yes, because our sins have been taken away by the Lamb of God who takes away the sin of the world, our Savior, Jesus Christ, and because the body and blood that He gives on His altar has touched our lips to make us clean, we can speak about the incomprehensible Triune God, Father, Son, and Holy Spirit. He opens our lips, that our mouths may declare His praise (Ps. 51:15). As with Isaiah in our text, He cleanses us, cleanses our mouths, so that we can speak His Word. Now, Isaiah was given to be a prophet, a divine office given in the Old Testament to speak God’s Word by direct revelation. None of us has that office today. But as pastor and people, as the royal priesthood of believers, we are given, each of us in our various vocations, to confess God, Father, Son, and Holy Spirit, to speak His Word to family and friends and neighbors and those whom God brings into our lives for this very purpose. We are given to praise Him, to speak forth the wonderful things He has done. That is what we do when we gather at the Divine Service to speak and sing the liturgy and the Psalms and hymns and prayers, all of it taken from Holy Scripture. This is just as mysterious as the Tri-unity of God, that sinners are declared righteous and made holy by God to speak of Him in confession and praise. It is by grace alone! We don’t deserve it. It is God’s gift to us in Christ.
“Blessed be the Holy Trinity and the undivided Unity. Let us give glory to him because he has shown his mercy to us” (Introit). That is where we are left in the face of the mystery of the Holy Trinity. Simply to praise, and then to go out and confess. “Here am I! Send me” (Is. 6:8). And God sends you to speak of Him to one another and to the nations, to support the Church and her mission with your prayers and gifts, to teach your children at home, and here at church in Sunday School and Vacation Bible School, to witness, to love and serve, and so to praise. For that is the praise our Triune God desires from you. To speak of Him to one another and to love and serve one another in His Name. He sends you, forgiven and cleansed, for this very purpose. The thrice-holy God sends you. You don’t understand Him. But you believe in Him. You trust Him. You confess Him. You praise Him. Because the Father created you and redeemed you by the blood of His Son, Jesus Christ, and has made you His own child by the new birth of water and the Spirit (John 3:5). You are baptized into Christ. You are baptized into the mystery of the Holy Trinity. And His very Name is on you, Father, Son, and Holy Spirit. “Holy, holy, holy, is the LORD of hosts” you will sing in a few moments in the Sanctus. And then you will come before God at His altar to receive the cleansing body and blood of Jesus in your mouth. Thus having been cleansed and strengthened by the Supper, you will go out, sent forth by God’s blessing, the one true faith confessing. You need not tremble at this, sinner though you be. Your guilt has been taken away, nailed to the cross of Christ. You belong to Him. You will not perish, but have eternal life. In the Name of the Father, and of the Son (+), and of the Holy Spirit. Amen.
 Cf. Luther's Small Catechism with Explanation (St. Louis: Concordia, 1991). pp. 105-07.