Job called on the earth not to cover his blood (v. 18) so it might cry to God for vindication (cf. Gen. 4:10). Job did not want people to forget his case when he died. He wanted someone to answer his questions and to vindicate his innocence even if he was not alive to witness it. The witness and advocate to which he referred (v. 19) seem to be some heavenly witness other than God since he called this person a man (v. 21).77Many commentators, however, believe Job had God in mind. Certainly the God-man, Jesus Christ, our advocate with the Father, is the person whom God provided to meet this need. However, Job did not have revelation concerning Him as far as the text indicates. Job longed for someone to plead with God for him since God was apparently ignoring his own cries. Moreover Job's companions were not pleading his case as true friends should have done (16:20; 17:2).
"With increasing clarity Job is seeing that satisfactory answers might be gained only when he has more direct dealings with God after death."78