"And I say to thee: That thou art Peter; and upon this rock I will build my church, and the gates of hell shall not prevail against it.” (Mt. 16:18). These words of Jesus are a great promise to all of mankind and to all Christians. Jesus, and not the people, is the one who builds the Church, and this Church remains in the teachings of her Redeemer, in spite of historical events and the sin of mankind. Peter – and his descendants – as bishop of Rome, the true rock which Jesus supports, is the sign and foundation of the unity of the Church, and the Church's faith.