"Yet the bible says, Who is our Rock save God. The church was built on the Rock of Jesus Christ, the foundation stone that the builders rejected."
Indeed it does. Yet another apparent contradiction, leading to the denominationalism that is exploding in the 21st Century, fragmenting Christianity into smaller and smaller sects.
The only ones that maintain a real link to the church of long ago are the Roman Catholic Church and the various Orthodox Churches.
The Church of I Disagree with Your Doctrine just doesn't have it so much together. And, boy, are there a lot of those out there. Hundreds...even thousands of denominations...each believing that it has the "right" interpretation of scripture.
And so it goes...as Christianity grows ever more fragmentary, it loses more and more of its commonality. Too bad.