This is exactly why Catholics believe in the authority of Peter as leader of the Church. God was the Rock and Christ said in front of all the Apostles that He was renaming Simon the Rock. He then said He would built His Church on that rock. He was speaking to fellow Jews who knew what Rock meant.
From the very first days of the Church, the disciples knew the authority to lead the Church on Earth had be given to Peter by Christ Himself with the renaming, which is always of great importance in the Bible, and the use of the word Rock, which had only been applied to God before that.
Again, Christ said it and it is faithfully recorded by the Holy Spirit in Scripture. Catholics take the Scripture very literally. We simply believe what Jesus said.
My hope is that all Christians and Jews will remember and declare that "The Rock" is a Name of God.
HE said NO such thing!
As you can see, Simon was already known as 'Peter'
NIV Matthew 4:18-19
18. As Jesus was walking beside the Sea of Galilee, he saw two brothers, Simon called Peter and his brother Andrew. They were casting a net into the lake, for they were fishermen.
19. "Come, follow me," Jesus said, "and I will make you fishers of men."NIV Matthew 8:14
When Jesus came into Peter's house, he saw Peter's mother-in-law lying in bed with a fever.NIV Matthew 10:1-2
1. He called his twelve disciples to him and gave them authority to drive out evil spirits and to heal every disease and sickness.
2. These are the names of the twelve apostles: first, Simon (who is called Peter) and his brother Andrew; James son of Zebedee, and his brother John;NIV Matthew 14:28-31
28. "Lord, if it's you," Peter replied, "tell me to come to you on the water."
29. "Come," he said. Then Peter got down out of the boat, walked on the water and came toward Jesus.
30. But when he saw the wind, he was afraid and, beginning to sink, cried out, "Lord, save me!"
31. Immediately Jesus reached out his hand and caught him. "You of little faith," he said, "why did you doubt?"NIV Matthew 15:13-16
13. He replied, "Every plant that my heavenly Father has not planted will be pulled up by the roots.
14. Leave them; they are blind guides. If a blind man leads a blind man, both will fall into a pit."
15. Peter said, "Explain the parable to us."
16. "Are you still so dull?" Jesus asked them.