Ephesians 2:8-10 For by grace you have been saved through faith, and that not of yourselves; it is the gift of God, Not of works, lest anyone should boast. For we are His workmanship, created in Christ Jesus for good works, which God prepared beforehand that we should walk in them.
I have always believed that texts such as these do not have sufficient precision or resolution, in and of themselves, to rule out the possibility that a possible act of "free will" acceptance is involved in the salvation process. In defence of this possibility, I will point out that the text identifies faith as a "gift", and the very way we use the concept of a "gift" necessarily entails an act of free-will acceptance. If faith is truly a gift as this concept is commonly used, the recipient has to have the in principle capability to freely reject the offer.
Even if this argument is not accepted, there is still the very real problem that one can construct a perfectly coherent model of the salvation process that is true to this text and also to the position that man has to freely accept the "faith" that definitely does originate in God (and not in us). The issues here are a little subtle, but such is the nature of this problem.
The argument sort of goes like this: I can lack a certain faculty, say the capability to understand quantum mechanics - I can be completely incapable of understanding the concepts, given my mental constitution. But even in such a state,
I can indeed recognize the existence of this lack of capability - I do not need to know any quantum theory to come to a recognition of my ignorance. I could then freely ask for help, say from a physics professor, who would then provide me with the knowledge and training that might enable me to eventually understand the theory.
In short, there is an important conceptual distinction between the
content of faith - which is indeed given to us by God - and the capability to recognize a need for this faith and ask freely for such faith to be given to me. The Ephesians text simply does not clearly state that we do not have this "capability" to recognize our need for faith and act freely on it. The text does, of course, rule out the possibility that we can construct such a faith of our doing.