Albert Barnes Commentary Job 17:5

"He that denounceth his friends for a prey, Even the eyes of his children shall fail." — Job 17:5 (ASV)

He who speaks flattery to his friends - Noyes renders this, “He that delivers up his friend as a prey, the eyes of his children shall fail.” So Wemyss, “He who delivers up his friends to plunder.” Dr. Good, “He that rebukes his friends with mildness, even the eyes of his children shall be accomplished.” The Septuagint, “He announces evil for his portion; his eyes fail over his sons.” The Vulgate, “He promises spoil to his companions, and the eyes of his sons fail.” The word rendered “flattery” (חלק chêleq) properly means “that which is smooth, smoothness” (from חלק châlaq to be smooth); and from there it denotes “a lot” or “portion,” because “a smooth stone” was anciently used to cast lots in dividing spoils (Deuteronomy 18:8).

Here it is synonymous with plunder or spoil; and the idea is, that he who betrays his friends to the spoil or to the spoiler, the eyes of his children shall fail. The meaning in this connection is, that the friends of Job had acted like someone who would announce the residence of his neighbors to robbers, so that they might come and plunder them. Instead of defending him, they had acted the part of a traitor. Schultens says that this verse is “a Gordian knot,” and most commentators regard it as such; but the above seems to give a clear and consistent meaning. It is evidently a proverb, and is designed to bear on the professed friends of Job, and to show that they had acted a fraudulent part toward him. In Job 17:4, he had said that God had hidden their heart from understanding, and that wisdom had failed them.

He here says that in addition to a want of wisdom, they were like a man who would betray his neighbors to robbers.

Even the eyes of his children shall fail - He shall be punished. To do this is a crime, and great calamity shall come upon him, represented by the failure of the eyes of his children. Calamity is not infrequently expressed by the loss of the eyes; see Proverbs 30:17.