He knows it, but he doesn't understand it. Wasn't he behind the crucifixion? Obviously, if he had understood how that would come out, he might have thought better of his design don't you think? I think it is the same thing with how the story ends. He knows the words, but he is still blinded by his pride and is without understanding. The scriptures are a mystery unless God's opens one's eyes to see. Satan still believes he can be greater than God, and whenever he gathers followers among men, his pride is nourished because he has proven able to steal away that which is most precious to God.
See, that's the part that's always puzzled me. We know he's a pretty sharp old codger. And unlike lost people who are smart enough to understand but yet fail to believe, there's surely no doubt in his mind as to the existence and divinity of God, and all the biblical history thereof. Which makes me think he understands, but thinks he can change the outcome, thinks he can in the end actually defeat God.
MM