Jesus’ words in Matthew 16:18 are the focus of an ongoing debate over who or what “the rock” is that Jesus mentions. The immediate context contains a question that Jesus put to His disciples: “Who do you say I am?” (verse 15). Peter answers, “You are the Messiah, the Son of the living God” (verse 16), to which Jesus replies, “Blessed are you, Simon son of Jonah, for this was not revealed to you by flesh and blood, but by my Father in heaven. And I tell you that you are Peter, and on this rock I will build my church, and the gates of Hades will not overcome it” (verses 17–18).
Is “this rock” on which Christ promised to build His church Peter? Is it Peter’s faith? Is it the truth of Peter’s statement? Or is the rock Jesus Himself? In all honesty, there is no way for us to be 100 percent sure which view is correct.
First view: the rock is Peter
One view is that Jesus was declaring that Peter would be the “rock” on which He would build His church. Jesus appears to be using a play on words. “You are Peter [petros] and on this rock [petra] I will build my church.” Since Peter’s name means “rock,” and Jesus is going to build His church on a rock, it appears that Christ means to link Peter with the founding of the church. It’s true that God used Peter greatly in the foundation of the church. It was Peter who first proclaimed the gospel on the day of Pentecost (Acts 2:14–47). Peter was also the first to take the gospel to the Gentiles (Acts 10:1–48). In a sense, Peter was the rock “foundation” of the church.
Second view: the rock is the truth contained in Peter’s statement
Another popular interpretation is that the rock Jesus was referring to is not Peter, but Peter’s statement of truth in Matthew 16:16: “You are the Christ, the son of the living God.” In this view, the “rock” is the truthfulness of that statement—the church is built on the rock-solid truth that Jesus is God’s Chosen One and the eternal Son of God. In confessing Jesus as the Christ, Peter, the “rock,” was demonstrating his own stability as he stood on that truth. He was, in a way, showing his character and why Jesus nicknamed him “Cephas” or “Peter” (see John 1:42).
Third view: the rock is Peter’s faith
Jesus had never explicitly taught the disciples the fullness of His identity, and so it was God who had sovereignly opened Peter’s eyes to that revelation. Jesus marks the source of that truth in Matthew 16:17. Peter’s confession of Jesus as the Messiah and Son of God poured forth from him as a heartfelt declaration of personal faith. Since personal faith in Christ is the hallmark of the true Christian, those who place their faith in Christ, as Peter did, are the church. Peter, writing to believers dispersed through the ancient world, likens them to stones used to build the church: “As you come to him, the living Stone—rejected by humans but chosen by God and precious to him—you also, like living stones, are being built into a spiritual house to be a holy priesthood, offering spiritual sacrifices acceptable to God through Jesus Christ” (1 Peter 2:4–5). The faith of believers is what makes them “living stones” able to be built into the church.
Fourth view: the rock is Jesus
After Jesus declares that God the Father had revealed the truth to Peter, He says, “You are Peter, and on this rock I will build my church” (Matthew 16:18). The word for “Peter,” Petros, is a masculine noun that means “a detached stone, a stone that might be thrown or easily moved” (Zodhiates, S., The Complete Word Study Dictionary: New Testament, AMG Publishers, 1992, p. 1,154). The word for “rock” next mentioned is a different Greek word, petra, a feminine noun that means “a mass of rock” or “a cliff” and therefore something foundational (ibid.; see also Matthew 7:24–25). The difference in the two terms may suggest that Jesus was contrasting Peter with Himself. That is, Jesus was saying, “You are the small rock, but I am the foundation of the church.” This view finds support in other passages that present Christ, not Peter, as the foundation of the church (1 Corinthians 3:11) and the life-giving rock (1 Corinthians 10:4).
Of course, the apostles played a foundational role in the building of the church (Ephesians 2:20), but the role of primacy is reserved for Christ alone. So, Jesus’ words in Matthew 16:18 are best interpreted as a simple play on words: a boulder-like, foundational truth came from the mouth of one who was called a small stone.
Christ Himself is called the “chief cornerstone” (1 Peter 2:6–7; cf. Matthew 21:42). The chief cornerstone of any building was that upon which a building is anchored. If Christ declared Himself to be the cornerstone, how could Peter be the rock upon which the church was built? Believers are the stones that make up the church. They are built upon the foundation of the apostles and prophets (not just Peter) and anchored to the Cornerstone (Ephesians 2:20). “The one who trusts in [Christ] will never be put to shame” (1 Peter 2:6).
The Roman Catholic Church argues that Peter is the rock upon which Jesus built His church, confers upon Peter the title of pope, and claims to be the one true church. As we have seen, however, identifying the rock as Peter is not the only valid interpretation of Matthew 16:18. Even if Peter is the rock upon which Jesus promised to build His church, it does not give the Roman Catholic Church any authority. Scripture nowhere records Peter being in Rome. Scripture nowhere describes Peter as being supreme over the other apostles. The New Testament does not describe Peter as being the all-authoritative leader of the early church. The origin of the Catholic Church is not in the teachings of Peter or any other apostle. If Peter truly was the founder of the Roman Catholic Church, it would be in full agreement with what Peter taught (Acts 2, 1 Peter, 2 Peter).