@King J. -- Scripture needs to be our foundation. The RCC holds Matthew 16:16 - 18 as a main text. Looking back at the context -- back starting with vs 13 "Who do men say that I, the Son of Man, am?"
vs 14 So they said, "some say John the Baptist, some Elijah, and others Jeremiah or one of the prophets."
vs 15 "He said to then, "But who do you say that I am?"
vs 16 "Simon Peter answered and said, "You are the Christ, the son of the living God."
vs 17 "Jesus answered and said to him, "Blessed are you, Simon Bar-Jonah, for flesh and blood has not revealed this to you, but My Father who is in heaven."
vs 18 "And I also say to you that you are Peter, and on this rock I will build My church, and the gates of Hades shall not prevail against it.
vs 19 "And I will give you the keys of the kingdom of heaven, and whatever you bind on earth will be bound in heaven, and whatever you loose on earth will be loosed in heaven."
Is not this passage stating that Peter is stating that he believes that he, Jesus, is the Christ, the Son of the living God and that God the Father is giving Peter this knowledge -- that the knowledge is that Jesus Christ is the 'rock' / foundation / that the Church being founded On.
That Hades will Not over-come the Church that is built on Jesus Christ as the Cornerstone / Foundation.
I'll admit that I don't really understand vs 19 -- I've heard an explanation For it which made sense at the moment I heard it. My basic understanding is that the 'keys' of the kingdom of heaven would be salvation. I don't understand why the word "key" is plural rather than singular.
But the most important concept is that Jesus Christ is the Cornerstone / Foundation of salvation / Christianity.