A New Prophet

Text: Deuteronomy 18:15-19

The Apostle John offers us a short and sweet sermon on our Old Testament text today in the first chapter of his Gospel. We’ll hear on Wednesday how,

The Word became flesh and dwelt among us, and we have seen His glory, glory as of the only Son from the Father, full of grace and truth…From His fullness we have all received, grace upon grace. For the law was given through Moses; grace and truth came through Jesus Christ.

John 1:14-17, English Standard Version

St. John, and Sts. Peter and Stephan with him – because they also preach on Deuteronomy 18 in the book of Acts – shows us that there is a difference between the ministry of Moses and that of our Lord Christ. Moses stands for the ministry of the Law, while Jesus stands for the ministry of the Gospel.

Both the Law and the Gospel are God’s Word, yet they have different goals; they produce different effects in our hearts. The preaching of the Law produces fear of God’s wrath and brings to repentance. The preaching of the Gospel comforts and soothes our hearts by telling us that Christ has borne our sins on the cross. It is this preaching that the Holy Spirit foretells through Moses in the text today. Here, Moses promises a new prophet who would be like us and preach God’s Word of Gospel.


In order for us to understand this text, it would be helpful for us, as Moses recalls, to turn back our minds to the giving of the Law on Mount Sinai. When the Lord led the people up out of slavery in Egypt, they walked across the Red Sea on dry ground. Then, for about three months, the Lord led them through the wilderness until they came to Mount Sinai. Once there, the people fasted and prayed for three days. On the third day, the Lord came down upon the mountain in a thick cloud of smoke. There was thunder and lightning, a loud trumpet blast, and the whole mountain rumbled. The people were forbidden from touching the mountain or even going near it, lest they be put to death. Out of the thunder, lighting, smoke and fire came the voice of God, “I am the Lord your God, who brought you out of the land of Egypt, out of the house of slavery. You shall have no other gods before Me.” (Ex. 20:2-3) The people were terrified, and they begged Moses – as we heard – that he speak to them in place of God.

The people were right to be afraid, God said, because they were experiencing the preaching of the Law in its full sternness. By the preaching of the Law, we mean the preaching of the Ten Commandments. The Commandments have always been written by God on our hearts, but they were delivered vocally and in writing on Sinai. They tell us which things are right and pleasing to God and the penalty for disobedience. The penalty for breaking a Commandment is severe because each transgression against these Ten Words is treason and hatred toward God. Because human nature has been corrupted by the Fall, we no longer recognize our own evil. Therefore, the Lord instituted the preaching of the Law – so that we might know our sins and repent.

This ministry continues even today. Through pastors, teachers, parents and other authorities, the Law continues to be preached and applied in our lives. It may be in a sermon, for example, that a sin we ourselves have committed may be mentioned, along with its penalty. Perhaps the Holy Spirit will work through one of the readings, and we’ll realize that something God forbids is exactly what we have done or are now doing. The point of this is so that we would know our sin and repent. When the people of Israel heard God’s thunder, they were so afraid they could die; would that we feel the same. The fact is, you and me deserve to die. We have disobeyed God’s commands and taken pleasure in our own evil. The thunder of God’s judgment would be just to roar against us.


Thankfully, however, the Lord does not just speak to us a Word of Law, but also a Word of Gospel. This is what the Holy Spirit promised through Moses when He said, “I will raise up for them a prophet like you from among their brothers. And I will put My Words in His mouth.” (Deut. 18:18) Moses, in his ministry, stands for the preaching of the Law. The purpose of this preaching is to show us our sins and bring us to repentance. The Law has no power to justify, though – following the Law cannot make us right with God. It only condemns and kills. But the Gospel, makes alive. The preaching of the Gospel sets us free from the condemnation of sin and death. That’s what the Holy Spirit promises in this text.

When it says that the Lord will raise up a prophet from among our brothers, it is foreshadowing the Incarnation. The Incarnation is the time, including now, when the eternal Son of God bears our same human flesh and blood. We confess every week in the Creed that Jesus was conceived by the Holy Spirit and born of the virgin Mary. According to the flesh, Jesus is descended from Abraham and it is therefore true that He is included as a brother of the children of Israel. Yet, He is also our brother because He shares with us our humanity. The same trials and temptations we bear, He shared. The same needs we have, He also felt – yet without sin. Jesus came to us to preach a new Word from the Father. Jesus Himself said, “I have not spoken on My own authority, but the Father who sent Me has Himself given Me a commandment—what to say and what to speak. And I know that His commandment is eternal life. What I say, therefore, I say as the Father has told Me.” (Jn. 12:49-50)

What Word did Jesus come to bring us from the Father? The Good News that Jesus Himself is our life and our peace. The rumbling of God’s thunder against us for our sins would be just, but the Father has chosen to show His justice in another way – by placing our sins on Jesus. The Baptist said that Jesus is the Lamb of God. Jesus is the sacrifice for all sin, yours and mine included. By His sinless life, by His death, by His resurrection, He has redeemed you and purchased you back from the powers of sin, death, and the devil. This is the Gospel: Jesus was born for you, and He died for you. He has broken you out of hell and brought you into His eternal life. You receive all these things not by your own merit, but freely by His grace.

This preaching sets our hearts a flutter, and not the bad kind of heart flutter. No, the preaching of Gospel sets us free and gives us joy. Knowing that our sins are forgiven, we can now hear God’s Law for what it is: good, right, and true. The things that He commands are good, and we should do them. That is why we remain here in the flesh, to live according to God’s will in love toward Him and each other. The Law, with its thunder and lightning, was set in place to show us our sins and bring us to repentance. For these reasons, it must be preached until the Last Day. Yet, the Lord promised through Moses – and has made good on it – a new Word, the Word of Gospel. By the Good News of Jesus’ birth, life, death, and resurrection, we are set free from sin and we will live eternally with Christ, our Lord and brother.

This last Sunday before Christmas is called, in Latin, Rorate Coeli. It comes from Isaiah 45 where it says, “Shower, O heavens, from above, and let the clouds rain down righteousness.” We confess and give thanks this week, that our Lord has looked upon us from above and rained down on us righteousness and peace through the birth of His Son, the prophet greater than Moses. In His name.

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