We have the saying ‘Seeing is believing’, that we believe a claim on evidence. But sometimes people can see, but not believe the evidence, forget, or get distracted. Jesus was frustrated with Israel’s religious leaders and his own disciples for seeing what he did, but not believing.
Only with the help of God did his disciples truly see that Jesus is the Christ, the Son of the Living God.
We are to see and believe that Jesus is the Christ, the Rock on which He builds his Church, the Church that will not die, and believers are given the Keys to the Kingdom of Heaven.