the fourth watch: The Jews at this time divided the night into four watches; the first was from six o'clock in the evening till nine, the second from nine to twelve, the third from twelve till three, and the fourth from three till six; so that it probably began to be daylight before our Lord came to his disciples. Matthew 24:43; Luke 12:38
walking: This suspension of the laws of gravitation was a proper manifestation of omnipotence. Job 9:8; Psalms 93:3-4, Psalms 104:3; Mark 6:48; John 6:19; Revelation 10:2, Revelation 10:5, Revelation 10:8