What does Matthew 16:18 really mean?

'Upon this rock' proves Peter (and his successors) is the foundation and head of the church. This is the most consequential reading-dispute in church history, so it deserves a plain-spoken answer. The Roman Catholic tradition reads 'this rock' as Peter himself, grounding papal succession on the verse. Most Protestant and Eastern commentators read it as Peter's confession of faith, or as Christ the one confessed. The Greek actually complicates the papal reading: Jesus shifts from petros (Peter's new name, a single stone) to petra (bedrock), suggesting a distinction, not an equation. Gill points out that whatever keys were given to Peter, the binding-and-loosing authority was immediately given to all the disciples in Matthew 18:18 — it was not Peter's exclusive possession. JFB and Henry both locate the rock in the act of Spirit-given confession, not in Peter's person or office. None of this makes Peter unimportant — he was clearly a pillar. But the verse itself does not settle institutional succession; it settles the church's survival. The closing promise — that the gates of Hades will not prevail — is the load-bearing claim, and on that point every tradition agrees.