John 6:17-19

and they got into a boat and started to cross the sea to Capernaum. It was already dark, and Jesus had still not come [back] to them. The sea was getting rough and rising high because a strong wind was blowing. Then, when they had rowed three or four miles [and were near the center of the sea], they saw Jesus walking on the sea and approaching the boat; and they were [terribly] frightened.