Jesus gave Simon a name based on the word for “rock.” Peter had just acknowledged Jesus to be the Son of God and the Messiah (Christ). Jesus used that as an opportunity to teach us about the importance of faith as the foundation of the church.
There were many variations on what people thought the Messiah would be. Some expected a political leader who would unite the Jews and maybe even overthrow their Roman masters. Others thought he would be a wonder-worker, a super-hero, who would use his power to make Israel a great and free nation. Some thought the messiah would provide food and riches in abundance.
In faith, we learn that Jesus has fulfilled all messianic hopes. He unites not just the Jews, but all people who believe in him. He sets us free from sin and death. He feeds our spiritual hunger with his own Body and Blood in the Eucharist.
By commending Peter’s faith, he shows us that faith is the foundation (rock) of the church. For the church is a family of people who believe all that Jesus taught because we believe in the person of Jesus. That is, we don’t just believe that Jesus was real. We affirm that he is alive and important to our lives. We have experienced him in his words, in the sacraments, and in each other. May our faith always be solid as a rock.