The following is taken from the Reformation Study Bible, R.C. Sproul general editor:
Proper understanding of the freedom of the will in the fallen human condition is assisted by distinguishing free agency from free will.
Free agency is a mark of humanity as such. All humans are free agents in the sense that they make their own decisions about what they do, choosing as they please in the light of their conscience, inclinations, and thoughts. They are answerable to God and to the rest of humanity for their choices. Adam was a free agent before the Fall, and afterwards. He continued to have desires and thoughts and to put them into action through his will. Similarly, we are free agents now; we will continue to be so after the resurrection. The glorified saints excercise their wills, but they are confirmed in grace, so that they cannot sin. Their choices are the product of human free agency, made in accordance with their nature, but now these choices are good and right. The transformation of their hearts is complete and they desire to do what is right.
Free will has been defined by Christian teachers from the second century on as the ability to choose any at all of the moral options offered in a given situation. Augustine taught that this possibility was lost through the Fall. The loss is part of the burden of original sin. After the Fall, our natural hearts are not inclined toward God; they are in bondage to sin and cannot be freed from this slavery except by the grace of regeneration. Such an understanding of the fallen will is taught by Paul in Romans 6:16-23.
Only a will that has been set free is able to choose righteousness freely and heartily. A permanent love of righteousness, that is, an inclination of the heart to the way of living that pleases God, is one aspect of the freedom that Christ gives (John 8:34-36; Gal. 5:1, 13).