Before the fall of Adam sinless man was able to sin. For God said, “In the day that you eat of it you shall surely die” (Genesis 2:17). As soon as Adam fell, sinful man was not able not to sin, since we were unbelieving, and “whatever is not from faith is sin” (Romans 14:23).
When we are born again, by the power of the Holy Spirit we are able to not sin, for “sin will have no dominion over you” (Romans 6:14). This means that what Paul calls “the natural man” or “the mind of the flesh” is not able not to sin. Paul says this in Romans 8:7-9
The mind that is set on the flesh is hostile to God, for it does not submit to God’s law; indeed, it cannot. Those who are in the flesh cannot please God. (See also 1 Corinthians 2:14).
How then shall we think of free will?
Bondage of the Will and Our Responsibility
It is not a saving power. In his freedom to will, fallen man cannot on his own do anything but sin. Such “free will” is a devastating reality. Without some power to overcome its bent, our free will only damns us.
We could stop here and turn with joy to the gospel truth that God overcomes our resistance, gives us life, wakens our dead inclination for Christ, and freely and irresistibly draws us to himself (John 6:44, 65; Acts 13:48; Ephesians 2:5; 2 Timothy 2:25-26). But it sometimes helps to answer objections. 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)