16:12. Then they understood that he said not that they should beware of the leaven of bread, but of the doctrine of the Pharisees and Sadducees. 16:13. And Jesus came into the quarters of Cesarea Philippi: and he asked his disciples, saying: Whom do men say that the Son of man is? 16:14. But they said: Some John the Baptist, and other some Elias, and others Jeremias, or one of the prophets. 16:15. Jesus saith to them: But whom do you say that I am? 16:16. Simon Peter answered and said: Thou art Christ, the Son of the living God. 16:17. And Jesus answering said to him: Blessed art thou, Simon Bar-Jona: because flesh and blood hath not revealed it to thee, but my Father who is in heaven. 16:18. 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. Thou art Peter, etc. . .As St. Peter, by divine revelation, here made a solemn profession of his faith of the divinity of Christ; so in recompense of this faith and profession, our Lord here declares to him the dignity to which he is pleased to raise him: viz., that he to whom he had already given the name of Peter, signifying a rock, St. John 1. 42, should be a rock indeed, of invincible strength, for the support of the building of the church; in which building he should be, next to Christ himself, the chief foundation stone, in quality of chief pastor, ruler, and governor; and should have accordingly all fulness of ecclesiastical power, signified by the keys of the kingdom of heaven. Upon this rock, etc. . .The words of Christ to Peter, spoken in the vulgar language of the Jews which our Lord made use of, were the same as if he had said in English, Thou art a Rock, and upon this rock I will build my church. So that, by the plain course of the words, Peter is here declared to be the rock, upon which the church was to be built: Christ himself being both the principal foundation and founder of the same. Where also note, that Christ, by building his house, that is, his church, upon a rock, has thereby secured it against all storms and floods, like the wise builder, St. Matt. 7. 24, 25. The gates of hell, etc. . .That is, the powers of darkness, and whatever Satan can do, either by himself, or his agents. For as the church is here likened to a house, or fortress, built on a rock; so the adverse powers are likened to a contrary house or fortress, the gates of which, that is, the whole strength, and all the efforts it can make, will never be able to prevail over the city or church of Christ. By this promise we are fully assured, that neither idolatry, heresy, nor any pernicious error whatsoever shall at any time prevail over the church of Christ. 16:19. And I will give to thee the keys of the kingdom of heaven. And whatsoever thou shalt bind upon earth, it shall be bound also in heaven: and whatsoever thou shalt loose on earth, it shall be loosed also in heaven.