I accept the authority of 66 Books, the Whole Bible. Which "Church" a passage is dealing with must be determined from the context where the word "church" is used.
The "church" of the Pauline Epistles is the Body of Christ of the current dispensation. The "church" of Acts 7:38 refers to the congregation, the assembly, of Old Testament Israel. "Church" in at least 115 passages in the New Testament refers to a local visible assembly of born-again Christians. The "church" of Matthew 16, however, is a believing congregation in an earthly, royal, Davidic, and Millennial Kingdom and has keys used for entrance.
I can see that about matthew 16. I've always believed that the rock that the church is built on is Christ though...his church (the called out ones not an organization) ARE not going to be defeated by death, or the gates of hades.