I find this a curious statement. It kind of changes the way I see the Fall and humanity's frailness and vulnerability to sin. It also brings into question God's knowledge of the Fall, his allowance of it, and what greater purpose it may have served if He knew about it and let it happen. Which, of course, also brings into question free will.
So. From my understanding, Lucifer is an angel who gets the boot from heaven because he wants to be God. To be honest, I'm not entirely sure where this idea comes from. I wiki'd Lucifer and found a bunch of different ideas. Either way, Lucifer gets sentenced to earth. I imagine Lucifer/Satan is probably bitter about the whole thing and wanders about his prison looking for something to destroy because he's so mad. He happens upon Adam and Eve and successfully convinces them that they can be like God-the same thing he got the boot out of heaven for.
Adam and Eve, meanwhile, have only ever been in relationship with God and whatever other animals they were surrounded by. They have never been confronted with evil and at first contact, fail miserably. Can they be at fault for this? Of course, they had God's "law" set for them-don't eat from this tree-but did God realize at the point of their failure that His law was not enough? Did God know when he made them that they would be inherently incapable of keeping His one command?
I guess I had always thought that God hatched the Jesus plan after the Fall-as a result of it. But what if that was the plan all along, before he ever made Adam and Eve, knowing that He would create vulnerable people that would need Him. Certainly makes current struggles easier to understand.
I realize I've made several assumptions, here. I kind of let thoughts roll to see what came out...feel free, as always, to leave comment.