john 6:19 So when they had rowed about five and twenty or thirty furlongs, they see Jesus walking on the sea, and drawing nigh unto the ship: and they were afraid. - Free Bible Online

      19. they see Jesus--"about the fourth watch of the night" (Mt 14:25; Mr 6:48), or between three and six in the morning.
      walking on the sea--What Job (Job 9:8) celebrates as the distinguishing prerogative of GOD, "WHO ALONE spreadeth out the heavens, and TREADETH UPON THE WAVES OF THE SEA"--What AGUR challenges as GOD'S unapproachable prerogative, to "GATHER THE WIND IN HIS FISTS, and BIND THE WATERS IN A GARMENT" (Pr 30:4) --lo! this is here done in flesh, by "THE SON OF MAN."
      drawing nigh to the ship--yet as though He "would have passed by them," Mr 6:48 (compare Lu 24:28; Ge 18:3, 5; 32:24-26).
      they were afraid--"cried out for fear" (Mt 14:26), "supposing it had been a spirit" (Mr 6:49). He would appear to them at first like a dark moving speck upon the waters; then as a human figure, but--in the dark tempestuous sky, and not dreaming that it could be their Lord--they take it for a spirit. (How often thus we miscall our chiefest mercies--not only thinking them distant when they are near, but thinking the best the worst!)

JFB.