Jesus lived three years with his disciples. They went everywhere together and did everything together. They ate, slept, and breathed the life of Jesus and yet it was difficult for them to make the transition in their minds from a Messiah who would be a mighty King of Jews to a Messiah that would die for the sins of mankind. But Jesus never wavered in his mission. Throughout his entire ministry among the people and his training of the disciples he held in his heart this hope: That Peter along with the rest of his disciples would lose their earthly ambitions and become feeders of sheep fishers of men.
The very first words of Jesus when he and Peter met at the waters was, "Follow me, and I will make you a fisher of men." His very last words to Peter, again down at the waters of the Sea of Galilee, and after his resurrection, were, "Feed my sheep, Follow me." From beginning to end this is the mission of the Church.