13 Now when Jesus came into the district of Caesarea Philippi, he asked his disciples, “Who do people say that the Son of Man is?” 14 And they said, “Some say John the Baptist, others say Elijah, and others Jeremiah or one of the prophets.” 15 He said to them, “But who do you say that I am?” 16 Simon Peter replied, “You are the Christ, the Son of the living God.” 17 And Jesus answered him, “Blessed are you, Simon Bar-Jonah! For flesh and blood has not revealed this to you, but my Father who is in heaven. 18 And I tell you, you are Peter, and on this rock I will build my church, and the gates of hell shall not prevail against it. 19 I will give you the keys of the kingdom of heaven, and whatever you bind on earth shall be bound in heaven, and whatever you loose on earth shall be loosed in heaven.” 20 Then he strictly charged the disciples to tell no one that he was the Christ.
In the name of Jesus, the Christ, the Son of the living God. Amen.
In Matthew 15:11, 17-18 Jesus says, “It is not what goes into a mouth that defiles a person, but what comes out of the mouth; this defiles a person. Do you not see that whatever goes into the mouth passes into the stomach and is expelled? But what comes out of the mouth proceeds from the heart, and this defiles a person.”
What you say reveals who you are and what is in your heart. The hatred and anger toward God and others that is in your heart comes out of your mouth. So when you cannot tell the truth about simple things, when you exaggerate the facts to make yourself look better, when you act like one person but are really another, you feel guilt. Your heart is black with sin and your mouth shows it. Repent.
Repent and hear what Jesus asks the disciples from our text, “Who do y’all say that I am?” Jesus doesn’t ask them if they were nice people or if they were making the world a better place with their good works. Jesus asks the one question that matters, “Who is Jesus?”
Peter answers for the disciples, “You are the Christ, the Son of the living God.” Jesus is the Christ, the Messiah, the Anointed One. Peter confesses, he says the same thing as God says. That’s what confession means. And Peter makes a right confession. A good confession. A Bible-based confession. And Jesus praises him for it, “Blessed are you Simon, son of Jonah. For flesh and blood has not revealed this to you, but My Father who is in heaven.”
Peter’s confession was not his own. Flesh and blood did not reveal it to him. God did. 1 Corinthians 12:3 says, “No one can say, ‘Jesus is Lord,’ except in the Holy Spirit.”
God had changed and cleansed Peter’s heart so that what came out of Peter’s mouth revealed a heart that had been forgiven and justified by God. As Romans 10:9-10 says, “If you confess with your mouth that Jesus is Lord and believe in your heart that God raised him from the dead, you will be saved. For with the heart one believes and is justified, and with the mouth one confesses and is saved.”
So, what Peter could not say on his own, God said for him and through him. God had purified Peter. God opened Peter’s lips that he might declare God’s praise (Ps. 51:15). Even though Peter was a deeply flawed and sinful man – a braggart and a denier – God still used him. God opened Peter’s lips for a right, true confession, “You are the Christ the Son of the living God.”
Peter confessed the first apostles’ creed because it was a confession of faith from the mouth of an actual apostle.
From Peter’s mouth came the very Word of God. Upon this rock – upon the Word of God, spoken on the lips of men – Christ builds His church. Jesus is the architect, the builder, and He even provides the material. This is the way God builds. God does what Peter could not do for himself and what you cannot do for yourself.
God still does this. God still builds His church on the right confession of who Jesus is. Jesus is the Messiah. He is the lamb of God who takes away the sin of the world. Jesus is the prophet greater than Moses. Jesus is the Redeemer, the good Shepherd, the King of kings. Jesus is the great high priest who intercedes for you before God the Father.
Upon the confession of Peter, the apostles, and all true believers, Jesus says upon this rock He will build His church, and the gates of hell will not overcome it.
Remember the Sunday school song? The wise man built his house upon the rock… The foolish man built his house upon the sand…
Jesus is no fool. He will not build His church upon anything but a sure, strong foundation. God does not build His church on what we do or even what we believe. That’s sand.
God builds His church upon the fact and confession that Jesus is the Christ, the Son of the living God.
Believer, God has given you the same confession as He gave to Peter, to the faithful believers of the Old Testament, and to all believers of all time.
This God-given confession of yours rises up from your heart which has been purified by grace and is uttered by lips cleansed in Baptism and Holy Communion. You too are Petros, a rock of Jesus Christ, and the gates of hell will not overcome you. Amen.
The peace of God which surpasses all understanding will guard your hearts and minds in Christ Jesus. Amen.
 Portions of this sermon were adapted from a sermon by Pr. David Petersen.