Albert Barnes Commentary Job 36:23

"Who hath enjoined him his way? Or who can say, Thou hast wrought unrighteousness?" — Job 36:23 (ASV)

Who hath enjoined him his way? - Who has prescribed to him what he should do? Who is superior to him and has marked out for him the plan which he should pursue? The idea is that God is supreme and independent; no one has advised him, and no one has a right to counsel him. Perhaps, also, Elihu designs this as a reproof to Job for having complained so much of the government of God, and for being disposed, as he thought, to prescribe to God what he should do.

Who can say, Thou hast wrought iniquity? - You have done wrong. The object of Elihu is here to show that no one has a right to say this; no one could, in fact, say it. It was to be regarded as an indisputable point that God is always right, and that however dark his dealings with people may seem, the reason why they are mysterious never is, that God is wrong.