Then Jesus said unto them, Yet a little while is the light with you. — It is better, as we have often seen, to read Therefore for “Then.” The word connects what follows closely with what has gone before. It was because of their question that Jesus said this. And yet it is not said that “He answered them,” because what He said was not a direct answer. They are asking questions in which we may trace the spirit, if not the very words, of the formal, literal objectors who had, with like technicalities, stifled the truth whenever it was springing up in their minds. Such questions cannot be really answered, because they are not really questions. And now the day has gone, and the night is at hand. The old thought comes back to Him (John 9:4; John 11:9). The last rays of light are shining. It is but a little while, and He warns them with all the solemnity of this thought.
Walk while ye have the light, lest darkness come upon you. — The better reading is, Walk according as ye have the light — i.e., “Walk as men who are conscious that the light is among them, use your opportunities; do not ask questions to raise objections, but ask them in order that you may know the truth.” The man who thus used the light would by no means walk in darkness, but would have the light of life (John 8:12). For him that neglected to use the means and faculty he had, both would cease to exist. (Comp. Note on Romans 1:21.)
The words “come upon,” or “overtake,” is used of some sudden seizure. There are two parallels in Biblical Greek, “But ye, brethren, are not in darkness that the day should overtake you as a thief” (1 Thessalonians 5:4), and “Be sure your sin will find you out” (Numbers 32:23).
He that walketh in darkness. — Comp. Notes in John 8:12; John 9:4; John 11:9; and 1 John 2:11.
Knoweth not whither he goeth. — The last word means “goeth away,” “departeth.” The frequent use of the word by St. John to express departure to the other world suggests that meaning here. He was going away. They ask, “Who is this Son of man who is lifted up,” “who goes away?” He warns them lest darkness seize them, and they go away into darkness. In the next four Chapter s the same word is used twelve times of Christ’s departure. (Comp. e.g. John 13:3; John 13:33; John 13:36.)