What does Matthew 16 13

Matthew 16: 13-20

Jesus said to him: Blessed are you, Simon Barjona; for it was not flesh and blood that revealed this to you, but my Heavenly Father. But I say to you: You are Peter and on this rock I will build my church and the powers of the underworld will not overpower it. I will give you the keys of the kingdom of heaven; What you will bind on earth will also be bound in heaven, and what you will loosen on earth will also be loosened in heaven. (Mt 16: 17-19)

Simon Barjona, only here does Jesus call him that. Is Matthew alluding to the sign of Jonah, which was spoken of immediately before? Like Jonah, is Simon a witness and herald in need of a second calling? We think here of his denial of Jesus and of the question of the risen one to him: "Do you love me?", Which John tells us. At the same time, Simon also bears the nickname Peter, the rock, and as this he becomes the foundation of the church. When Jesus speaks of the powers of the underworld, Matthew is certainly alluding to the gates of Hades, before which Jesus was standing with his disciples. No dark power, however powerful it may seem, can overwhelm the kingdom of God, because it is firmly founded on a rock that is mightier than the rock of Caesarea Philippi.

As a conceivable solid foundation of the salvation community to be built up by the Messiah Jesus, Simon should be the safeguarding principle of its existence and its unity. And in this function he will be endowed with mediating power, as the figurative word of the handing over of the keys to the kingdom of heaven and the transfer of binding power of binding and redemption add explanatory. (Anton Vögtle)

God wants the church. His revelation should not be interpreted by every person arbitrarily, but God himself appoints people who say in his name what he wants to have said. It is Peter who bears witness to Jesus in the name of everyone and on behalf of God, and on Peter as the reliable witness appointed by God, Christ builds his church, which cannot be shaken by anything. So the church is the guarantor for the truthful communication of God's revelation. In this Church of his God God repeatedly calls people who give testimony of the truth in his name.
One can object that the church is made up of many faulty people and that a lot of injustice has also been done through the church. Without a doubt, the Church is made up of people with their faults. Peter was weak too, he will deny Jesus. But the church is more than the people in it. The church is the bride of Christ whom he has wed. Hence Christ loves the Church and guides her through all difficulties. He repeatedly calls people to make up for the mistakes of others, as far as that is possible. Therefore the church as a whole is holy and cannot be wrong in the long run.
Jesus loves his church. He wants us to love the Church too, that we stick to her, despite all the flaws we see in her. Jesus wants us to be in unity with the successor of the apostle Peter, the Pope in Rome. When we are connected in love with and listen to the Church, then we also learn the truth about who Jesus Christ is.

Then he commanded the disciples not to tell anyone that he was the Messiah. (Mt 16:20)

Jesus is the Messiah that Israel has been waiting for and who proclaims God's light and wisdom to the whole world. The disciples now know for sure. But this secret is still hidden from other people. Only after Jesus' death and resurrection should it be announced to the whole world. They are necessary for the Messiah to fulfill all of God's righteousness. Jesus speaks of this necessity in the following words, and there we will also see that despite the great words that have come to him, Peter still remains a weak person who has yet to learn what it means to follow Jesus.