For a while both Jesus and John the Baptizer were teaching the people and telling them to repent (that is, to chance their mind away from sin.) But then king Herod put John the Baptizer in prison and finally had his head cut off because he did not like John's preaching. But Jesus kept teaching and healing people and doing miracles.
A little while later Jesus went north with his disciples to Caesarea Philippi. While there he asked his disciples, "Who do people say that I, the son of man, am?" and they said, "some people say that you are John the Baptizer; others say you are Elijah, still others say Jeremiah or one of the old prophets come back from the dead." Then Jesus said to his disciples, "you are the Christ, the son of Jonah. It was not a person who shoed you this, but it was my father who is in heaven."
The Jesus went on to say, "I tell you, you are Peter. And I will build my church on this rock. The gates of Hades will not win against it. I will give you the keys of the kingdom of heaven. The things you don't allow on earth will be the things that God in heaven does not allow. The things that you make free." Then Jesus warned his disciples not to tell anyone that he was the Christ (Matthew 16:13-20; Mark 8:27-30; Luke 9:18-21)
Peter had been with Jesus enough to know that he was not just a man. He had seen Jesus heal people and do miracles. He had heard Jesus teach. And he knew that Jesus must have come from God. The stories about Jesus are not just stories to enjoy. They are true stories that help us to understand who Jesus was. They were written so that we might believe that Jesus is the Son of God and Thus have eternal life (John 20:31).
When Jesus told Peter that he would build his church, he was not talking about a church building. He was not even talking about a church organization, although in English we call both a church building and a denominational organization a "church". The Greek word fro church means "a group of people who meet together". Christ called his people a church because they will all meet together in the sky when he comes again (1 Thess. 4:17). Sometimes we hear people say that there are over 300 different churches (that is, denominational organizations) in the United States, and that their church is the only true one. This is to miss the point of what Jesus said. It is true that he said "my church" (just one), and not "my churches". But he was not speaking of any denominational organization. He did not start a denominational organization, and no denominational organization is the true church. All of them were started by men. The church that Jesus was speaking of was his group o people God adds everyone who is saved to that Hades cannot win against. Hades is the place where the spirits of the dead people wait for the end of the world. But Jesus, who was to rise from the dead and who will bring his people back to life also, said that Hades cannot hold on to his people. He will bring us all back to life in a great victory over death (1 cor. 15:51-57). Truly Jesus is the Son of God.