Upon This Rock

In Matthew 16:18 it says,” I also say to you that you are Peter, and upon this rock I will build My church; and the gates of Hades will not overpower it” (NASB). With this being a major foundation of the Catholic Church, I think it is important to have a good understanding of this scripture that would begin with looking closely at it in its original context.
The Catholic Church interprets the scripture this way, as taken from Catechism of the Catholic Church 936; The Lord made St. Peter the visible foundation of his Church. He entrusted the keys of the Church to him. The bishop of the Church of Rome, successor to St. Peter, is "head of the college of bishops, the Vicar of Christ and Pastor of the universal Church on earth"
When examining Matthew 16:18 we need to remember 2 Peter 1:20-21, and that interpretation is not a matter of one’s own opinion but rather by what GOD originally intended. So with that in mind we will look at the context, and examine the verses surrounding this passage, so looking at Matthew 16:13-19 we may get a better understanding of what is being said: “13Now when Jesus came into the district of Caesarea Philippi, He was asking His disciples, "Who do people say that the Son of Man is?" 14And they said, "Some say John the Baptist; and others, Elijah; but still others, Jeremiah, or one of the prophets." 15He said to them, "But who do you say that I am?" 16Simon Peter answered, "You are the Christ, the Son of the living God." 17And Jesus said to him, "Blessed are you, Simon Barjona, because flesh and blood did not reveal this to you, but My Father who is in heaven. 18"I also say to you that you are Peter, and upon this rock I will build My church; and the gates of Hades will not overpower it. 19"I will give you the keys of the kingdom of heaven; and whatever you bind on earth shall have been bound in heaven, and whatever you loose on earth shall have been loosed in heaven."
While reading this and keeping context in mind, we must remember how Jesus’ ministry has gone thus far; People both opposing and adoring Him, and with this in mind Jesus asks His apostles both: Who do the people think He is? And who do you think I am? Peter replies, “You are the Christ, the Son of the Living GOD.” And it is upon this statement when observing the context of the passage, that Jesus is not saying “upon this rock”, Peter, but rather upon this enormous truth which Peter just proclaimed; that Jesus is the Christ.
And it is not just from this passage in Matthew 16 that we find the Bible observing Christ Jesus as the rock or referencing GOD; definitely not Peter. In Isaiah 44:8 it says,” Is there any GOD besides Me? No, there is no other Rock; I know not one.” Or in Psalm 18:1,” For who is GOD besides the LORD? And who is the Rock except our GOD.”
Furthermore, Peter knowing those scriptures just noted would never have taken what Jesus said to him in that manner; and even his lifestyle and writings help bring light to that. In Acts 2 when Peter and the rest of the apostles address the crowd on Pentecost, you see that Peter not only doesn’t claim to be the foundation but points to Jesus and calls Him the “stone rejected by the builders, which has become the capstone.”
Paul also wrote, “No other foundation can be laid other than the one already laid, which is Jesus Christ” (1 Corinthians 3:11).
One more thing that I find important regarding the matter is that there may be an assumption that this idea of Peter being the foundation has been understood by all from the beginning; I want to negate that thought with just a couple numbers comprised of what previous “fathers” in the Catholic Church understood Matthew 16:18 to say. “17 understood the rock to be Peter, 8 the apostles, 44 Peter’s confession of faith in Christ, 16 Jesus Christ Himself, and a few the faithful in general” (Answers To Questions Catholics Are Asking). You see the majority put either in Peter’s confession; disproving the thought that this practice has been around from the beginning.
So in having closely examined the passage Matthew 16:18 I believe we may conclude that until more recently in our history it has always been understood that Jesus, and not Peter, was the foundation or rock upon which the church was built; and that it was those people who down the line misconstrued and misinterpreted the message that was originally and, I believe, still intended.

http://www.vatican.va/archive/ccc/index.htm
Catechism of the Catholic Church
Answers To Questions Catholics Are Asking
By: Tony Coffey