John Piper discusses concisely, Scripturally, and intellectually the issue of man’s free will in his recent blog post. Assuming you understand his conclusion, I thought that this ending argument was profound and powerful:
One common objection is that, if we “cannot” do what is right, and “can only” do what is sin, then we are not acting voluntarily and cannot be praised or blamed.
Here is part of John Calvin’s answer to this objection:
The goodness of God is so connected with his Godhead that it is not more necessary to be God than to be good; whereas the devil, by his fall, was so estranged from goodness that he can do nothing but evil.
Should anyone give utterance to the profane jeer that little praise is due to God for a goodness to which he is forced, is it not obvious to every man to reply, “It is owing not to violent impulse, but to his boundless goodness, that he cannot do evil?”
Therefore, if the free will of God in doing good is not impeded, because he necessarily must do good; if the devil, who can do nothing but evil, nevertheless sins voluntarily; can it be said that man sins less voluntarily because he is under a necessity of sinning? (Institutes, II.3.5)
What an excellent illustration Calvin provides to answer such a frequent objection!