"Be careful not to convince yourself that you are doing something against your will. Such a thing is impossible."
I am master of my own life. That is my personal power. I choose what I do, how I act or react to circumstances, what I choose to think or feel, whether I am optimistic or pessimistic. Not all my choices are good, sometimes I have to choose the least negative of my options. But the choice is mine.
Lack of understanding of this law causes people to do things they would not normally do. What comes to mind immediately is the hold some people seem to hold over others. Because a person believes they are at the mercy of another persons' will, they will allow themselves to do as the other wants.
When we understand that we are responsible for our own actions and for what we allow to influence us, such things as black magic and voodoo loose their power over us. Even minor influences are negated. We can not be made to do anything against our will. We can even conquer fear. That is true power! We truly become a master, we have gained mastery over ourselves. It is ultimately the only power and the only mastery that counts.
There is a small experiment to see how easily we can let others affect us when we do not know that we are in control. We give away that control on the subconscious level without even knowing it. If you tell someone that they are looking a little ill, and reinforce it a few times, that person can actually convince themselves they are ill. If that person knows they are in control, your comments will not affect them.