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 grace of regeneration. Such an understanding of this fallen will is taught by Paul in Romans 6:16-23.
Here is that passage:
16 Do you not know that to whom you present yourselves slaves to obey, you are that one’s slaves whom you obey, whether of sin leading to death, or of obedience leading to righteousness? 17 But God be thanked that though you were slaves of sin, yet you obeyed from the heart that form of doctrine to which you were delivered. 18 And having been set free from sin, you became slaves of righteousness. 19 I speak in human terms because of the weakness of your flesh. For just as you presented your members as slaves of uncleanness, and of lawlessness leading to more lawlessness, so now present your members as slaves of righteousness for holiness.
20 For when you were slaves of sin, you were free in regard to righteousness. 21 What fruit did you have then in the things of which you are now ashamed? For the end of those things is death. 22 But now having been set free from sin, and having become slaves of God, you have your fruit to holiness, and the end, everlasting life. 23 For the wages of sin is death, but the gift of God is eternal life in Christ Jesus our Lord.
The article concludes:
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 the living that pleases God, is one aspect of freedom that Christ gives (John 8:34-36; Gal. 5:1, 13).