But he said to them, "I AM. Don't be afraid."

 6:16-21 When evening came, his disciples went down to the sea, and, when they had embarked upon a boat, they started across the sea to Capernaum. By this time darkness had come on, and Jesus had not yet come to them; and the sea was roused because a great wind was blowing. So, when they had rowed between three and four miles, they saw Jesus walking on the sea, and coming near the boat, and they were afraid. But he said to them: "It is I; don't be afraid." So they wished to take him on board the boat; and immediately the boat reached the land for which they were making. 