The “Rock” or foundation the church (community) of Jesus Christ is built upon is; the revelation that Jesus is the Christ, the Son of the living God. That is what the Father revealed to Peter and that is the foundation Jesus’ church is built on.
The “Rock” or foundation >>of<< the church
We are all little pebbles (servants) of God. Our God is so Great he even uses evil people as servants to further his Kingdom. Think about it when you break a big boulder into pieces what are you left with, a bunch of little rocks... WE ARE THE CHURCH ALL BELIEVERS a bunch of little pebbles bound together with Jesus Christ as our Head all leading to and Glorifying the Loving Father.