Job says that his own efforts to prove his innocence would be acting wrongly before God. AT: "my own words would accuse me" (See: [[rc://en/ta/man/translate/figs-metonymy]])
Possible meanings are 1) Job's mouth will declare that Job is wrong or 2) God will declare that Job is wrong AT: "my mouth will say that I am wrong" or "God will say that I am wrong"