I'd try to resurrect Jesus Christ. If it worked, I would have resurrected God's human form for us to inquire to, or we would know he was merely a man (since I would assume that a God who isn't "dead" can't be resurrected). At the very least just ask him face to face. If it didn't work at all, then we'd know no such person ever existed. Sounds like a way to get some answers anyhow.

If I had both they'd cancel each other out. Probably.