We... must learn again and again the lessons that Peter himself had to learn between that moment of sudden understanding - You're God's Messiah! - and the time when he stood up in front of a surprised Jerusalem crowd on the first Pentecost morning and announced fearlessly that God had shown Jesus of Nazareth to be Messiah and Lord through his resurrection. (I should say, just for the record, that the idea that Peter himself, rather than his faith in Jesus as Messiah and Lord, was the rock on which the church would be built, and that this was to be passed on to his successors as Bishops of Rome, was an exegetical innovation in the counter-Reformation period of the late sixteenth century, when you get those remarkable settings of the Latin text of Matthew 16, 'Tu es Petrus, et super hanc petram aedificabo ecclesiam meam', 'You are Peter, and on this rock I will build my church'. It is always frustrating when splendid music makes the wrong theological point, and I'm afraid those motets are examples of that problem.)

No; the point is this: when you confess Jesus, crucified and risen, as God's Messiah, and Lord of the world, you are taking your stand upon the rock to which Jesus himself, and Peter himself in his first letter, refer, the rock where the true city of God is being built, even though the gates of hell roar their anger against it and do their best to distract us from the hot and tiring pilgrim journey by which we must come to it at last. 'Come to him,' writes Peter, 'to that living stone; and like living stones yourself be built into a spiritual house, to be a holy priesthood offering spiritual sacrifices to God through Jesus Christ.' And the letter goes on to reflect, from the Old Testament, on the image of the stone, the rock, cornerstone of the Temple, capstone for the corner, and underneath it all the rock which is the true Zion, the foundation of the whole place. All earthly houses of prayer, if they know what they are about, are designed not as ends in themselves but as signposts along the steep and stony road to that true Zion: as, at best, foretastes of what is still to come: 'I know not, O I know not, what joys await us there; what radiancy of glory, what light beyond compare'.

More... http://www.ntwrightpage.com/sermons/Dusty_Road_Golden_City.htm