God doesn't prevent terrible things because?

[dsgrue3]

The Fury said:

Licence said:

Free Will. It's about the idea of faith and trust. If God is oniscient then he could know all possibilities of the future just not which future it is (if he knew what Cain would say then there is only one future and therefore Free Will is an illusion/lie).

Omniscience means exactly that - knowing all, including what Cain would say. If free will makes omniscience impossible then we can't go around saying God is omniscient. 

I never said it God didn't know, he knows all possible outcomes of the conversation just not which one of those possibilties Cain will make with his Free Will (God knows all). If God knows only 1 possible outcome then Free Will is a lie and no one needs to do anything thinking they are doing it from their choice, because it's already been predetermined for us.

Except omniscience implies foreknowledge...thus negating your entire argument.