Matthew 16:18 “So I now say to you: You are Peter, and on this rock I will build my community {That is, congregation}. And the gates of the underworld can never overpower it.”
We do not deny Christ’s words ever, rather, we look into what was the context and on the same or similar terms used to get the best understanding of what they believed in.
We examine carefully, who was the rock? If it is assumed Peter is the rock, why would Jesus build his congregation upon a man who did not die for all mankind?
If the rock was Jesus, then all the pieces fit in together as Revelation 1:18 says Jesus would not die evermore, so also would anyone who believes him would come to have eternal life (John 3:16), yet that does not mean they could not die, because Jesus’ example is that he did once but would have the promise of resurrecting and therefore death would not overpower them sufficiently when compared to eternal death (never coming to life again). The church as a whole would not be allowed to be “dead” so-to-speak forever but the word does allow for it to be temporarily inactive, but ultimately not forever.
Ephesians 2:20 defines who the rock he referred to is, “You are built upon the foundations of the apostles and prophets, and Christ himself is the cornerstone.” 1 Corinthians 10:4 “For nobody can lay down any other foundation than the one which is there already, namely Jesus Christ”. (Confirmed by 1 Corinthians 3:11) So going against that would be apostasy since it is well stated in the Bible.