Jamieson, Fausset and Brown on Job 33:8

8. thy words--(Job 10:7; 16:17; 23:11, 12; 27:5, 6; 29:14). In Job 9:30; 13:23, Job had acknowledged sin; but the general spirit of his words was to maintain himself to be "clean," and to charge God with injustice. He went too far on the opposite side in opposing the friends' false charge of hypocrisy. Even the godly, though willing to confess themselves sinners in general, often dislike sin in particular to be brought as a charge against them. Affliction is therefore needed to bring them to feel that sin in them deserves even worse than they suffer and that God does them no injustice. Then at last humbled under God they find, affliction is for their real good, and so at last it is taken away either here, or at least at death. To teach this is Elihu's mission.