Matthew 16:18-19 "And I say also unto thee, That thou art Peter, and upon this rock I will build My Church; and the gates of hell shall not prevail against it. And I will give unto thee the keys of the kingdom of heaven: and whatsoever thou shalt bind on earth shall be bound in heaven: and whatsoever thou shalt loose on earth shall be loosed in heaven."
Before I attempt to explain this passage, I would like to make an observation that is not based upon what is specifically stated in the text, but what I believe Jesus meant. Peter's statement of faith in the true identity of Jesus (v. 16), is the rock. It is the foundation for upon which the Lord is building His Church. The Apostle Paul described the Church as a building having Christ as its foundation (1 Cor. 3:9-11). Jesus said, "Whosoever cometh to Me, and heareth My sayings, and doeth them (evidence of true faith), I will shew you to whom he is like: He is like a man which built an house, and digged deep, and laid the foundation on a rock: and when the flood arose, the stream beat vehemently upon that house, and could not shake it: for it was founded upon a rock" (Lk. 6:47-48).
Notice that those who, by faith, recognize Jesus as their Lord, obey Him, unlike those who say, "Lord, Lord..." and yet are busy being religious (Matt. 7:21-22; 25:11; Lk. 6:46; 13:25). It is faith in Jesus that is the foundation of one's salvation (Eph. 2:8-9), and it is faith in Jesus that results in doing the Lord's will (Eph. 2:10). It is also interesting to note that "faith," πίστις (pistis) in the Greek, like the word "rock," is a feminine noun. So, in other words, faith (Matt. 16:16) is the foundation (Lk. 6:47-48; 1 Cor. 3:9-11) upon which Christ is building His Church.
In Matthew 16:19, Jesus said to Peter, "And I will give unto thee the keys of the kingdom of heaven: and whatsoever thou shalt bind on earth shall be bound in heaven: and whatsoever thou shalt loose on earth shall be loosed in heaven." Notice that "keys" is plural. Does that mean there is more than one door to heaven? No, there is only one and that is Jesus (Jn. 10:7. 9). So one of the "keys" has to be faith in Jesus, the only Door to heaven.
The other "key" has to be to the "gates of hell" (Matt. 16:18). The sole purpose of a gate is to control who enters and who exits a specific property. The "gates of hell" are obviously intended to keep the lost from escaping. The fact that the word is plural indicates that there are many ways to enter, but in the case of hell, none are intended to allow those residing there to exit. Satan apparently has his gates locked. However, Jesus gave Peter the "keys." The Church can open the gates and free those who are willing to come out. The "key" to the gates of hell is the Gospel of Jesus Christ; it is the power of salvation (Rom. 1:16)! More on Peter and the keys tomorrow, Lord willing.