The mind is free when it follows virtue and rejects vice. It is free when it listens to the soul and maintains its authority over the body. To do so, it must harden its will and discipline its thoughts and desires, so that it leads them rather than being led by them. Such a mind grows strong. It becomes an instrument of God’s will. Blessed are those who control themselves so they may help others.
The Straight Path: A Religious Guide to Finding and Fulfilling One’s Purpose, p. 5.