Adam Clarke on Job 36:21

Regard not iniquity - It is sinful to entertain such wishes; it is an insult to the providence of God. He sends affliction; he knows this to be best for thee: but thou hast preferred death to affliction, thereby setting thy wisdom against the wisdom of God. Many in affliction, long for death; and yet they are not prepared to appear before God! What madness is this! If he takes them at their wish, they are ruined for ever. Affliction may be the means of their salvation; the wished-for death, of their eternal destruction.