John Gills Exposition of the Bible Commentary

Verse 21 (Job 36:21)

Take heed, regard not iniquity ,.... Not any iniquity, as to show any approbation of it, love for it, and desire after it. All appearance of sin, of every sin, is to be abstained from; but particularly by the iniquity here meant may be the sin of impatience under his affliction; murmuring at the dealings of God with him; arraigning his justice, and saying very indecent things of him, as in Job 34:5 . Or it may mean the evil he had been guilty of in so earnestly desiring the night of death:

for this thou hast chosen rather than affliction ; chose rather to die than to be afflicted as he was; or chose rather to complain of God, as if he dealt hardly with him, and did not do justly by him, than to submit patiently to the will of God, as he, ought to have done: or this he chose "through affliction" F4 מעני "prae afflictione", Junius & Tremellius, Piscator; "prae miseria ex adflictione", Michaelis. ; through the force of it, because of it, and by means thereof; and so is a sort of excuse that Elihu makes for him; though at the same time he would have him by no means to regard such iniquity, and indulge to it.

- John Gills Exposition of the Bible Commentary