(4.5) The secret of thoughts creative power is spiritual activity.
(4.15) The degree of harmony we attain is determined by the degree in which we realize that we can not change the infinite but must cooperate with it.
(4.25) Constructive thinking is the ability to adjust our thought process to the will of the Universal; to cooperate with natural law.
Spiritual activity is cause an effect. All thought is a cause and how we feel is the effect. Thus, we must take responsibility for thoughts, because there is no other way to secure peace. This method of intentional thinking called is constructive thinking.
(4.26) This is accomplished by securing a perfect understanding of the principle forces, methods, and combinations of mind.
(4.16) The law of attraction rests on vibration which–in turn–rests on love. This is the principle which gives thought its dynamic power. Any thought impregnated with love is invincible.
(4.6) We may acquire the faith, courage, and enthusiasm that results in achievement by a recognition of our spiritual nature.
We learn about mind through actively observing its habits. Love adds vitality to thought (4.3), which empowers cause and effect with momentum. As we begin to experience the effects of constructive thinking, we become confident of our spiritual nature.
Aperture of Brahma 