Mt 14:28-31
Peter said to him in reply, "Lord, if it is you, command me to come to you on the water." He said, "Come." Peter got out of the boat and began to walk on the water toward Jesus. But when he saw how (strong) the wind was he became frightened; and, beginning to sink, he cried out, "Lord, save me!" Immediately Jesus stretched out his hand and caught him, and said to him, "O you of little faith, why did you doubt?".