“And I tell you, you are Peter, and on this rock I will build my church, and the gates of hell shall not prevail against it.”
Jesus says this right after Peter declares that he is the Christ, the Son of the living God — the promise is born as a response to a correct recognition of who Jesus is.
Peter and rock sound alike in the original language — Jesus uses the disciple's own name to point toward the foundation he's about to build on.
Jesus is the one building, and the church belongs to him — Peter is foundation, not owner, and that distinction protects the church from depending on any one human leader.
Gates were defensive structures in antiquity, not offensive ones — the image suggests it's the advancing church doing the attacking, and death that can't hold its ground.
The promise is of ultimate victory, not the absence of hardship — the church would go through real persecution, but no power would ever manage to destroy it.
Act: Think of a difficulty your local church is facing and pray with confidence, declaring that even that difficulty will not prevail against what Jesus is building.