When it was evening, the boat was in the middle of the sea, and He was alone on the land. Seeing them straining at the oars, for the wind was against them, at about the fourth watch of the night He came to them, walking on the sea; and He intended to pass by them. But when they saw Him walking on the sea, they supposed that it was a ghost, and cried out; for they all saw Him and were terrified. But immediately He spoke with them and said to them, “Take courage; it is I, do not be afraid.”  Then He got into the boat with them, and the wind stopped; and they were utterly astonished, for they had not gained any insight from the incident of the loaves, but their heart was hardened.
Mark 6:47‭-‬52 NASB
http://bible.com/100/mrk.6.47-52.NASB