“Then Jesus answered and said, ‘Blessed art thou, Simon Bar-Jona, for flesh and blood has not revealed this to thee, but my father in heaven. And I say to thee, 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 thee the keys of the kingdom of heaven; and whatever thou shalt bind on earth shall be bound in heaven, and whatever though shalt loose on earth shall be loosed in heaven” (Matthew 16:17-19)
Now to break down and define the meaning of this passage:
1) “And I say to thee, thou art Peter, and upon this rock I will build my Church” Opponents of the Catholic interpretation of Matthew 16:18 sometimes argue that in the Greek text the name of the apostle is Petros, while "rock" is rendered as petra. They claim that the former refers to a small stone, while the latter refers to a massive rock; so, if Peter was meant to be the massive rock, why isn’t his name Petra?
Note that Christ did not speak to the disciples in Greek. He spoke Aramaic, the common language of Palestine at that time. In that language the word for rock is kepha, which is what Jesus called him in everyday speech (note that in John 1:42 he was told, "You will be called Cephas"). What Jesus said in Matthew 16:18 was: "You are Kepha, and upon this kepha I will build my Church."
When Matthew’s Gospel was translated from the original Aramaic to Greek, there arose a problem which did not confront the evangelist when he first composed his account of Christ’s life. In Aramaic the word kepha has the same ending whether it refers to a rock or is used as a man’s name. In Greek, though, the word for rock, petra, is feminine in gender. The translator could use it for the second appearance of kepha in the sentence, but not for the first because it would be inappropriate to give a man a feminine name. So he put a masculine ending on it, and hence Peter became Petros.
The word ‘rock’ is merely a play on words. In Aramaic there is no difference between the word for rock and Kepha, Peter. Some people will attempt to claim that the “rock” mentioned by Jesus isn’t Peter personally, but a vague attitude of faith on the part of all true believers. This idea, however, has long since been discredited by serious Catholic and Protestant biblical scholars; there’s overwhelming scholarly agreement that Peter alone is the rock to which Jesus refers.
2) “and the gates of hell shall not prevail against it.” The gates of hell could mean the gates of death, but more naturally mean the powers of hell. They will not prevail. So if the Church founded by Christ had taught the wrong way to salvation for most of 1500 years, until Luther, the promises of Christ would be practically worthless. The Church as such, as identifiable, would have been in gross error until Luther was sent by God to correct it! So, God is promising that the Church will stand with Peter’s, and his successors, guidance against all the attacks of Satan and his followers. This also means that the Church would be free from error.
3) “And I will give thee the keys of the kingdom of heaven” "Keys" of course signified power to rule, as is obvious. Keys to important objects, such as money safes, gates, doors, cash drawers are entrusted to those with authority and/or power. Jesus is giving the “keys to the kingdom” to Peter; which can only mean he is entrusting to him the authority and power to govern, teach, and guide the Church. The promise there made by Christ, finds its explanation in Isaiah 22, in which "the key of the house of David" is conferred upon Eliacim, the son of Helcias, as the symbol of plenary authority in the Kingdom of Juda. Christ by employing this expression clearly designed to signify his intention to confer on St. Peter the supreme authority over His Church.
4) “whatever thou shalt bind on earth shall be bound in heaven, and whatever though shalt loose on earth shall be loosed in heaven” What does “bind and loose” mean? Well, it is another way of saying to forgive or not to forgive sins. Here Peter was singled out for the authority that provides for the forgiveness of sins and the making of disciplinary rules. Later the apostles as a whole would be given similar power [Matt.18:18], but here Peter received it in a special sense.
To be continued……..
***Note that large portions of this information are taken from Catholic sources, namely: New Advent Online Catholic Encyclopedia, EWTN website, Catholic Answers, Catholic Catechism of the Catholic Church, and “Christian, Yes- But Why Catholic? Helpful Ideas on Explaining and Defending Your Faith” by Rev. Joseph M. Esper.***