Job 36:4 For truly my words are not false; one who is perfect in knowledge is with you.
Norman Giesler writes:
Historically, the omniscience of God was a straightforward doctrine: God knows everything—past, present, and future; He knows the actual and the possible; only the impossible (the contradictory) is outside the knowledge of God…
THE BIBLICAL BASIS FOR GOD’S OMNISCIENCE
…“Can anyone teach God knowledge?” (Job 21:22). “Be assured that my words are not false; one perfect in knowledge is with you” (Job 36:4)…
Giesler quotes Elihu as his evidence of God’s omniscience. In context, Elihu is making an argument. The argument goes like this: Job, my words are true. God is giving me His infinite knowledge to tell these things to you. God micromanages the affairs on Earth. The wicked are justly punished. You are one of these wicked.
Elihu is wrong. The point of the book of Job is that Job is not wicked. He is receiving an unjust punishment. Elihu is numbered among Job’s friends, and makes their same arguments. God condemns Job’s friends. Elihu is not a good source for prooftexting theology.
On the same hand, Elihu is not making Giesler’s point. To Elihu, God is “perfect” in knowledge. The same word is used of man in Job 12:4. Man can be “perfect”. Attaching undo theological weight to this concept is stretching the text. It likely is just idiomatic for God is very knowledgeable, a concept Giesler would likely deny. In the Classical view, God’s knowledge is not like ours.