Are there not twelve hours in the day? — Or more exactly, Are not the hours of the day twelve? They had expressed their fears that danger and death would be the result of going into Judæa. His answer would say that the darkness of the night which they dreaded could not come yet. The natural night would come not until its appointed hour, until the twelve hours of the day had run their course. The day of His life is marked out by limits no less sure. The night indeed cometh, but it is as yet full day, and in that day He and they must do the work which is appointed of the Father. (Comp. John 11:6; and Notes on John 2:4; John 7:30; John 8:20; John 9:4; John 12:27; John 17:1.)
Incidentally these words bear on the question of St. John’s method of counting the hours of the day, and support the view which from other passages seems quite evident that he follows the ordinary Babylonian numeration. (Comp. Notes on John 1:40; John 4:6; John 4:52; John 19:14.)
Because he seeth the light of this world — i.e., the natural light of the sun. While the earth is illumined by it, men follow the course of their work without danger of stumbling. In the application to their own position, the truth holds good. The day of His work is illumined by the light of heaven, and for Him and them there is safety.