Isaiah 22:20-23 And it shall come to pass in that day, that I will call my servant Eliakim the son of Hilkiah: (21) And I will clothe him with thy robe, and strengthen him with thy girdle, and I will commit thy government into his hand: and he shall be a father to the inhabitants of Jerusalem, and to the house of Judah. (22) And the key of the house of David will I lay upon his shoulder; so he shall open, and none shall shut; and he shall shut, and none shall open. (23) And I will fasten him as a nail in a sure place; and he shall be for a glorious throne to his father's house.Keys open and close things, so any reference to keys might have such language. But notice the key in Isaiah is not plural, not "keys" but "key." So we have a discrepancy in the purported analogy.
Revelation 3:7-8 And to the angel of the church in Philadelphia write; These things saith he that is holy, he that is true, he that hath the key of David, he that openeth, and no man shutteth; and shutteth, and no man openeth; (8) I know thy works: behold, I have set before thee an open door, and no man can shut it: for thou hast a little strength, and hast kept my word, and hast not denied my name.Note here the key is singular, as it encompasses all that is entailed in being the true Prime Minister of Israel. The church at Philadelphia was dealing with what Jesus called the synagogue of Satan, those of Israel who like the Pharisees had thoroughly rejected Jesus as Messiah. But here Jesus tells them that He, not they, holds the key to the authority of David's house, and that He will keep their door open, and no man can shut it.
Matthew 18:18 Verily I say unto you, Whatsoever ye shall bind on earth shall be bound in heaven: and whatsoever ye shall loose on earth shall be loosed in heaven.The power of binding and loosing, by which Jesus described the keys in Matthew 16, is thus applied equally to all twelve apostles in Matthew 18. Furthermore, no principle of exclusion is stated which restricts it to those twelve only, but in principle any follower of Christ, in preaching the Gospel, may be instrumental in many different forms of loosing and binding, everything from the loosing or binding of sinners through Gospel preaching, to the binding and loosing of judgments in church discipline. Thus the apostles unlocked the doctrine and build a secure foundation as God gave them revelation, and the elders and other servants of local congregations build on that foundation by applying that doctrine to the practical circumstances of their flocks, all of which may be seen in terms of a multiplicity of loosings and bindings (plural keys), but not as in any way competing with the one key of Messianic governance, which Scripture explicitly tells us is held by King Jesus Himself.
How dare you involve context in your exegesis! That ruins everything. Scripture means whatever an RC says it does if it support Rome.