In my mind I can hear Peter and John talking through what they were seeing. They were examining how and where the cloths were lying and what might have happened. It says that John saw and believed. The word saw here is a different word from the other two in the previous verses. The word for saw here means “to understand”. Have you ever had something to click in your mind and you say “oh now I see?” John put the evidence together with what Jesus had told them and it created belief in him. Faith is believing what Jesus says before the evidence occurs. That is how we are to live; stepping out in faith and watching God bring it to pass.