Albert Barnes Commentary Job 16:3

"Shall vain words have an end? Or what provoketh thee that thou answerest?" — Job 16:3 (ASV)

Shall vain words? — The marginal note says: "In Hebrew, 'words of wind'"; that is, words devoid of thoughtful insight, and trifling. This is a retort to Eliphaz. He had charged Job (Job 15:2–3) with uttering only such words. Such forms of expression are common in the East. “His promise, it is only wind.” “Breath, breath: all breath.” Roberts.

Or what emboldeneth thee? — “What provokes or irritates you, that you answer in this manner? What have I said that has prompted such a speech—a speech so severe and unkind?” The Syriac reads this as, “Do not afflict me any more with speeches; for if you speak any more, I will not answer you.”