Theophylact of Ohrid
Catena Aurea · Markusevangelium 6
And straightway he constrained his disciples to get into the ship, and to go to the other side before unto Bethsaida, while he sent away the people. And when he had sent them away, he departed into a mountain to pray. And when even was come, the ship was in the midst of the sea, and he alone on the land. And he saw them toiling in rowing; for the wind was contrary unto them: and about the fourth watch of the night he cometh unto them, walking upon the sea, and would have passed by them. But when they saw him walking upon the sea, they supposed it had been a spirit, and cried out: For they all saw him, and were troubled. And immediately he talked with them, and saith unto them, Be of good cheer: it is I; be not afraid. And he went up unto them into the ship; and the wind ceased: and they were sore amazed in themselves beyond measure, and wondered. For they considered not the miracle of the loaves: for their heart was hardened.
See again how Christ, though He was about to put an end to their dangers, puts them in greater fear. But He immediately reassured them by His voice, for it continues, And immediately he talked with them, and said unto them, It is I, be not afraid.