Why is it that the only mention of Peter receiving the keys to the Kingdom of Heaven and being the rock upon which Christ’s Church will be built is in one gospel (Matthew)? Wouldn’t we expect to find such an important moment elsewhere within the other gospels as well, particularly in the Gospel of Mark? After all, it was Mark who wrote his gospel based off of what Peter had told him. It doesn’t seem likely that Peter would have left out this detail. I appreciate everyone’s responses.