Christians who is the "Rock"?

The apostle Jesus was speaking to was named Simon. When Jesus told Him "Thou art Peter", that was the first time anyone had addressed him by that title, which literally means "Rock". Thereafter he is referred to in Scripture as "Simon Peter", which means "Simon the Rock". Pretty straightforward! In the very same sentence where Jesus assigned this title to Simon, He also said Simon was to be the Rock upon whom His Church would be built. To ensure that Simon is able to carry out that unique mission, Jesus then gave him supreme authority, symbolized by "the keys to the kingdom", and the charism of infallibility, telling him "Whatsoever you bind upon earth is bound in heaven". You are correct in saying that Jesus IS "The Rock" of our salvation! Which is what makes it so significant that Jesus, The Rock, used the same term in appointing His personal vicar on earth, the first Pope of His Holy Catholic Church!