God promises that He absolutely will accomplish His purposes. Let’s say that when Christ was slain, God offered salvation to everyone. He did not know who would accept it until they did accept it. This opens the possibility that not a single person could have chosen to be saved at all. This then means that God might have failed to accomplish His purpose. I’m struggling to look at it any other way.
I also tend to look at free will as us just being able to do what we are most inclined to do. This leaves room for us being totally dependent upon God for even coming to faith in Christ. And it thus makes sense that a direct work of the Holy Spirit is essential or else none of us would be saved.
And while that is where I am personally, I have to admit that the Molinist position, that a true free will decision, if it is truly free and autonomous, cannot be known ahead of time because it does not exist anywhere yet nor have any determining forces even by God been exerted upon the actor. Is God still all knowing? Yes, God knows all possible autonomous choices, and has contingent plans for all free decisions that will be made. And God also knows enough about our makeup that he knows some will freely believe. But like
@Silverhair insists, if God himself gives you a choice, do we have any right to say we don't have a choice.
It sounds stupid at first but yet if you look at several scriptures you wonder. God acts like he was going to wipe out the Israelites and start all over with Moses at one point. And Moses talks him out of it. God seems to say to Abraham now I know you will obey me. God seemed to just flat out say that Ninevah was toast but then they all seemed to make a free will decision to humble themselves and God (changed his mind?) and spared them. In a system like this God will certainly have his will ultimately accomplished. But it does explain how we can have genuine free will choices which let's face it, multiple scriptures seem to act as if that is the case.
When I first heard of this from William Lane Craig I thought it was nonsense, but after listening to him debate James White I thought he held his own pretty well.