Your Mind is Your Master by Napoleon Hill

You had nothing to do with your coming into this world. You may have little or nothing to do with your leaving it. But you have almost everything to do with your life while you possess that life. You can be the master of your fate, the captain of your soul by the simple process of taking possession of your own mind and using it to guide your own life without meddling in the lives of others.
Notice the connection between mastering yourself and not attempting to master others. A major reason for unhappiness is the tendency to meddle with the lives of others while we take too little time in trying to perfect our own.
Nobody else can do the job of taking possession of your mind, nor should you permit anyone else to try. Your mind is your master; yet your mind can be such a kindly master that it responds to your needs and desires and finds ways to make them come true when they are definite. All other creatures on earth are bound throughout their lives by a fixed pattern of instinct from which they cannot escape. YOU are bound only by the pattern you set up in your own mind. YOU are limited by nothing else.
Source: Grow Rich with Peace of Mind. Random House. 1996. Pg. 128.
Article By: Napoleon Hill.