Job 11:6 (ESV)

6 and that he would tell you the secrets of wisdom! For he is manifold in understanding. Know then that God exacts of you less than your guilt deserves.

Job had asked why God was not willing to pardon the sins that he had committed (Job 7:21). Zophar now responds that God had indeed forgotten some of Job’s sin. If he had not, Job’s punishment would have been far worse.