In a talk given by Father John Corapi on the subject, he first explained that in the Old Testament, frequently God was referred to metaphorically as “Rock”.
According to one author I read, God is referred to roughly 20 times in the Psalms as “Rock”.
One example would be Psalm 144:1 -
Blessed be the LORD my Rock, Who trains my hands for war, And my fingers for battle.
Some other places in the Old Testament where this occurs :
- Deuteronomy 32:3-4,
- Deuteronomy 32:18
- 1 Samuel 2:2,
- 2 Samuel 22:2
- 2 Samuel 22:32
- 2 Samuel 23:3
… With honourable mention going to the stone (reference to Christ) in Psalm 118:22 and Isaiah 8:14 .
Then Father Corapi’s interpretation goes on to say that after Peter made his profession , “Thou art the Christ the Son of the living God”, and Christ replied, “Thou art Peter(
Kepha - as Abu points out) and upon this rock I shall build my Church”, Christ is actually saying to Peter, “I am going to graft you to myself.”
I found that to be a very thought provoking interpretation.