When evening came, his disciples went down to the lake, where they got into a boat and set off across the lake for Capernaum. By now it was dark, and Jesus had not yet joined them.  A strong wind was blowing and the waters grew rough.  When they had rowed about three or four miles, they saw Jesus approaching the boat, walking on the water; and they were frightened.  But he said to them, “It is I; don’t be afraid.” Then they were willing to take him into the boat, and immediately the boat reached the shore where they were heading. 

John 6:16-21