Jesus went into the region of Caesarea Philippi and he asked his disciples, "Who do people say that the Son of Man is?" They replied, "Some say John the Baptist, others Elijah, still others Jeremiah or one of the prophets." He said to them, "But who do you say that I am?" Simon Peter said in reply, "You are the Christ, the Son of the living God." Jesus said to him in reply, "Blessed are you, Simon son of Jonah. For flesh and blood has not revealed this to you, but my heavenly Father. And so I say to you, you are Peter, and upon this rock I will build my church, and the gates of the netherworld shall not prevail against it. I will give you the keys to the kingdom of heaven. Whatever you bind on earth shall be bound in heaven; and whatever you loose on earth shall be loosed in heaven." Then he strictly ordered his disciples to tell no one that he was the Christ.
This passage contains what appears to be a broad grant of power to the Church: “Whatever you bind on earth shall be bound in heaven; and whatever you loose on earth shall be loosed in heaven.” It seems strange that God would give us human beings, who are so prone to error, prejudice, and self-dealing, the ability to make decisions for Him.
Jesus routinely quotes the Old Testament prophets, and his actions regularly parallel action in the Old Testament. For instance, Jesus’s overturning of the money changers tables in the Temple remind the apostles of Psalm 69 – “zeal for Thy house consumes me.” The same Psalm includes, “I was thirsty and they gave me vinegar to drink,” just as Jesus was given vinegar on the Cross.
Jesus’s statement to Peter in this Sunday’s Gospel mirrors a statement made by Isaiah in the Old Testament too, an excerpt of which is this Sunday’s first reading. In it, Isaiah informs Shebna (who held an office equivalent to Secretary of State of Judah under King Hezekiah) that he will be removed from office for pridefully building a grand tomb for himself. And, in fact, his tomb was found in Siloam and its lintel, bearing Shebna’s name, currently resides in the British Museum. Isaiah prophesies that Shebna will be replaced by Eliakim:
I will place the key of the House of David on Eliakim's shoulder; when he opens, no one shall shut when he shuts, no one shall open. I will fix him like a peg in a sure spot (Isaiah 22)
The passage closes with a statement that the peg will someday give way and fall.
So, in quoting this passage, Jesus is doing something other than granting Peter authority to make decisions for God. He is declaring that Peter has been chosen to lead the Church by God, thus removing those who exhibited too much pride, and he may even be predicting Peter’s eventual removal from office by execution.