John Gill 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 that speaketh flattery to [his] friends
As Job's friends did to him when they promised great outward prosperity, and a restoration to his former state, and to a greater affluence upon his repentance and reformation; or when they spoke deceitfully for God, pretending great regard to the honour of his justice and holiness, and therefore insisted on it that he must be a wicked man and an hypocrite, that was afflicted by him, as Job was:

even the eyes of his children shall fail ;
so hateful are some sins to God, and particularly deceitful tongues, and flattering lips, that he will punish them in their posterity; the eyes of their children shall fail for want of sustenance, and while they are looking in vain for salvation and deliverance out of trouble, see (Exodus 20:4) .