Rock

 

In the Aramaic language that Jesus spoke the word for rock was "kepha." Jesus would have said to Simon, "You are kepha and on this kepha I will build my church." In the Greek of Matthew 16:16-19 "Petros" is the name and "petra" is rock (this picture was taken at Petra in Jordan.) To catch Jesus' wordplay, we would best translate, "You are Rock and on this rock I will build my church."
Jesus gives Peter a leadership role for the community of believers. In other places in the Gospels Peter is the acknowledged leader and spokesman for the apostles.
There is nothing in the scriptures that says that the bishop of Rome was intended to be Peter's successor as leader of the community of believers. That development happened for several reasons. Peter (and Paul) had been martyred in Rome.
Rome was the capital of the Empire, the Gentile world to which the Christian mission was increasingly directed. As early as the first century the leader of the Church in Rome began in letters to show care for other churches in the Empire.
For almost a thousand years the bishop of Rome held together under his leadership the community of those who believe in Jesus. The papal ofice symbolized and promoted the unity of the Church. Then the Orthodox and Roman churches separated. Several hundred years later the Protestant Reformation challenged the leadership of Rome. The Rock that had once been the symbol of Church unity had become a stumbling block.
In recent years some Protestants have begun to see the value of some central authority and some Catholics have begun to see that we have exaggerated the extent of the Pope's power. If these trends continue. perhaps some day the papal office will once more symbolize and create Christian unity.