Matthew 14:28-33 (ESV)
And Peter answered him, "Lord, if it is you, command me to come to you on the water."  He said, "Come." So Peter got out of the boat and walked on the water and came to Jesus.  But when he saw the wind, he was afraid, and beginning to sink he cried out, "Lord, save me."  Jesus immediately reached out his hand and took hold of him, saying to him, "O you of little faith, why did you doubt?"  And when they got into the boat, the wind ceased.  And those in the boat worshiped him, saying, "Truly you are the Son of God."
Sorry, I can’t help but read baptism into this, to just draw about 50,000 parallels. Peter’s fears and doubts concerning Jesus drown in the waters as Jesus pulls him back out by the hand. It is then that Peter confesses Jesus to be the Son of God.
Peter is in a perfectly good boat, but like a sky diver who thinks it great fun to jump out of a perfectly good airplane, this Peter thinks it would be great fun to walk on water with Jesus. Of course the storm is particularly bad, and the wind and the waves have managed to pull the disciples further out to sea than they cared to go, seasoned fishermen that most of them were. This was not a light storm. The wind shakes Peter’s confidence, deprives him of faith. He was fine until he saw the wind. His faith kept him above. But he began to sink, as his faith faded. Jesus was using Peter’s faith to allow him to walk. But Peter knows that Jesus can still save him. He cries a prayer of faith “Lord save me!”
Truth is our own faith is never enough to get us through this life. Whether it be wind or wave, our faith is sometimes strong, and sometimes weak. We fall. But Christ is always there to pick us up. He sustains our faith.