If we had nothing but the Book of Job to go by, and we had to interpret the Book of Job through the Book of Job, then we would be compelled to look at Job 9:32-33, which read as follows:
Job 9:32-33 (NASB)
32 For He is not a man as I am that I may answer Him, that we may go to court together.
33 There is no umpire between us, who may lay his hand upon us both.
The Hebrew word translated for “there is no” is יש with the negative לֹא. That is, Job was not implying by his choice of words that such an umpire did not exist, in which case he would have used the Hebrew word אין, but that in fact he was not present, and so he used יש with the negative לֹא. (In Spanish we would say, “no está” –not here– as opposed to saying “no hay” –none exists–.) For example, when God says to Satan that there was no righteous man on earth like Job (Job 1:8 and Job 2:3), we see the word אין, which means that no other man like Job existed. In fact, in the passage we are looking at (Job chapter 9) the word אין occurs twice in one verse (Job 9:10), suggesting that there is no amount of inquiry in existence or no number in existence, which can quantify the great things and wondrous works that God performs. (No finite quantifications exist!) But in the SAME CHAPTER (in Job 9:32) Job does not use the word אין, but the negative form of יש with the negative לֹא, which means that the arbiter, who would place his hand on both God and Job, is not “non-existent,” but that he is not present at hand at that moment. So we see this unidentified “umpire” early in the Book of Job who will arbitrate between God and man, but who is not present. Such an arbiter would have to be an equal party to both sides, since no mortal man places his hand on the most high God and calls arbitration on behalf of other human beings.
Fast forward to Job 19:25. Job’s “Redeemer” now appears. The Hebrew word for redeemer is גאל, which not only means someone who redeems something, but someone who fulfills justice by exercising the right of redemption. For example, the “גאל of blood” was someone who fulfilled divine justice by seeking the life of the killer (Numbers 35:19-27, Deut 19:6-12; and Joshua 20:2-5). The redeemer therefore exercised his right as a part of a legal proceeding. We are all familiar with Boaz, the redeemer, who entered the court at that time at the city gates, and received the shoe to close the legal proceedings in order to redeem both the land and Ruth the Moabitess. He exercised his legal right after another kinsman declined to exercise the same right. Boaz exercised the law, and therefore redeemed Ruth as an act of justice.
So who is this redeemer? He is the one “who lives” (Job 9:25) but who is not yet present. He is therefore the umpire, who will arbitrate between God and man, and therefore will fulfill justice “when he takes his stand on earth” (Job 9:25).
If Job had access to words of Enoch, who lived before Job (please reference Jude 1:14-15 for the words of Enoch), then Job would have known that when he comes to take his stand on earth, this umpire who will arbitrate justice is none other than the Lord himself.
[In the New Testament, he is revealed as the God-man, who is equal with man and is equal with God, and therefore is the priest-king according to the order of Melchizedek.]