Development of a Positive Mental Attitude by Napoleon Hill

A subject of paramount importance in the development and maintenance of a positive mental attitude is believing where belief is justified. Let us review some of the circumstances which call for belief:
Acquire an enduring belief in the existence of Infinite Intelligence from which your Creator makes it possible for you to receive the power necessary to help you take possession of your own mind, and direct it to whatever ends you may choose.
Acquire an enduring belief in your ability to become free and self-determining as your greatest gift from your Creator. You should demonstrate this belief in actions fitting to its nature.
Believe in that way of life and form of government which guarantees the freedom and precious privileges for which men in every century and all parts of the world have fought and died.
Believe in those with whom you are associated in your occupation or calling in life, and recognize that if they are not worthy of your complete belief, you have the wrong associates.
Believe in the power of the spoken word and see to it that you speak no word which does not harmonize in every respect with your positive mental attitude.
Source:  PMA Science of Success Course. Educational Edition. The Napoleon Hill Foundation. 1983. Pg. 231.