Read Matthew 14:22-15:11.
To me the miracle is not Jesus walking on water, but Peter trying. Peter gets a bum rap in the gospels - worse in Mark, by the way, than in Matthew who seems to try to clean Peter up a little. But what Peter has in spades, it seems to me, is chutzpah - and the contemporary Church could use a lot more of that.
So, okay, the Son of God is walking on water. Pretty cool trick. But Peter says, "I think I might be able to do that, with God's help." In fact I might be able to do infinitely more than I can ask or imagine - with God's help. But let's start here. I'll try.
So he gets out of the boat and starts walking toward Jesus. And it's going along fine, until he notices a wind, a strong wind, and he becomes frightened. And that is when he begins to sink.
Jesus is a tough teacher. Peter was the only one who volunteered to try, but now he gets, "Ye of little faith...why did you doubt?"
My former parishioners could quote me I'm sure, because I probably said it once a month over fifteen years - that the opposite of faith is fear. Fear paralyzes us. Fear is the enemy of spiritual growth.
Faith is not about what we believe in our heads. It's about chutzpah.