While our Saviour was praying on the mount the ship which carried his disciples was upon the sea, that is, that creek of the sea which they were at that time passing over. A storm ariseth, not without the counsel of God, that Christ might show that both the winds and the waves were under his command.
And in the fourth watch of the night, that is, about three hours before the rising of the sun; for though the Jews anciently divided the night into three parts, each consisting of four hours, yet being at this time under the Romans, they kept to their division of it into four parts, which they called watches, from their military guards, which they relieved every three hours.
Jesus went unto them, walking on the sea, as if it had been firm ground.
And when the disciples saw him walking on the sea, they were troubled, saying, It is a spirit, and they cried out for fear. By this it seemeth that the doctrine of spirits was not strange to that age, though they had a sect of Sadducees which denied it. That the devil, by God’s permission, hath a power to trouble and agitate the air, and also to assume a visible shape, and in it to affright persons by sea or by land, is unquestionable. When the disciples at distance saw Christ walking on the sea, they concluded it was some such apparition. This made them cry out through fear.
But straightway Jesus spake unto them, saying, Be of good cheer; it is I; be not afraid. Mark addeth, Mar_6:52, They considered not the miracle of the loaves; for their heart was hardened. Having had so late an experience, both of the power and goodness of their Master, in their late strait for want of bread, they ought not so soon to have showed a distrust in his providence, as if he would have suffered them to have perished in the sea: that miracle did not make a due impression upon them.