“What is the nature of free will?” someone once asked Rebbe Nachman. The Rebbe answered him very simply, “Free will is in a person’s hands, literally. If one wants, one acts. If one does not want, one does not act.”
Reb Natan adds:
I recorded this, because it makes a very important point. Many people are very confused about this issue. They see themselves caught up in their habits and helpless to change their ways. They feel that they no longer have free will. But the truth is otherwise. Everyone certainly possess free will at all times to act or not to act as one wants. Understand this well!
Likutei Moharan II: 110