Blog 181: 4.6.4 - 4.6.9
In defending the prerogatives of the pope as the successor of Peter, Roman Catholics commonly appeal to Matthew 16:19, where Jesus says to Peter, "I will give you the keys of the kingdom of heaven, and whatever you bind on earth shall be bound in heaven, and whatever you loose on earth shall be loosed in heaven."
On Calvin's interpretation, the "key" to heaven is simply the gospel of Jesus Christ, to which people are bound by faith or else loosed by unbelief. This gospel key was not given to Peter alone, however; it was also given to his fellow apostles (see John 20:23). Therefore, the Catholics are mistaken when they give to Peter (still less, the pope) personal authority over heaven and hell.
Roman Catholics also appeal to Matthew 16:18, where Jesus says to Peter, "Upon this rock I shall build my church." Calvin is willing to grant that in the building of the church, Peter was given the honor of first placement as a living stone. Yet he denies that this honor gives him any primacy over other members of the church. According to Peter himself, we are all "living stones" that are built on the cornerstone of Christ (see 1 Pet. 2:5-6).
As we read the gospel accounts of Peter and the other disciples, or consider the relationship between Peter and the apostle Paul (see especially Galatians 2:7-14), or observe Peter's role at the Council of Jerusalem (see Acts 15), it is clear that Peter was equal to the other apostles.
But even if we grant that Peter was the first among equals, or that the other apostles yielded primacy to him, the Roman Catholics have no warrant for extending his leadership to the whole world. The church has only one head: Jesus Christ.