The Rock is Jesus
In His Own Words, Jesus said He is the Word and God's Word is the Rock:
Matthew 7:26And every one that heareth these sayings of mine, and doeth them not, shall be likened unto a foolish man, which built his house upon the sand:
Luke 6:49But he that heareth, and doeth not, is like a man that without a foundation built a house upon the earth; against which the stream did beat vehemently, and immediately it fell; and the ruin of that house was great.
Without "moisture" even those on His Rock who don't "hear" will wither away:
Luke 8:8And other fell on good ground, and sprang up, and bare fruit a hundredfold. And when he had said these things, he cried, He that hath ears to hear, let him hear.
Jesus didn't want those who don't receive the Word to be "saved":
Luke 8:13They on the rock are they, which, when they hear, receive the word with joy; and these have no root, which for a while believe, and in time of temptation fall away.
Paul confirmed that Jesus, NOT PETER, is the Rock:
Romans 9:33As it is written, Behold, I lay in Sion a stumblingstone and rock of offence: and whosoever believeth on him shall not be ashamed.
1 Corinthians 10:5But with many of them God was not well pleased: for they were overthrown in the wilderness.
And now we are to believe that Jesus referred to Peter and not the Word as the Rock?:
Matthew 16:19And 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.
Clearly Jesus was referring to the Word of God as "the Rock" in this verse, just as He was in previous verses, and just as Paul was. For the Roman Catholic Church to now claim that it was founded by Peter would be ok IF, and only IF, this "church" did not fit to a tee the people who Jesus said CANNOT be saved. Which part of God's Word does this "church" now "heareth these sayings of mine, and doeth them"?
Even Peter himself condemned this very "church" which claims him as their founder because they "stumble at the word [read: the rock]" with every move they make:
1Peter 2:9But ye [are] a chosen generation, a royal priesthood, an holy nation, a peculiar people; that ye should shew forth the praises of him who hath called you out of darkness into his marvellous light: