Nowhere specific, but rather by deduction. However, the thought occured to me when I read 33:23 ff. Elihu is a young man, but wise-- wiser than the older men. He is a newcomer to the scene who does not refute the OT but gives a new perspective on it. He rebukes the older men for their misunderstanding of Job, his situation and God. Then in the verses above, he gives us a proto-Gospel. Words like mediator, v 23, ransom, v 24, and restoration, v. 26, and the fact that someone else is redeeming the offender,v. 28, 29. In following chapters and verses I see some elaboration on this.

Do I read too much into it?

Stand Fast, Craigellachie!