A lustful mind can never know things of the Spirit or deep things of God. The carnal mind cannot grasp spiritual things, things which are beyond the grasp of the intellect. Saturate your mind with thoughts divine. Check the rising of evil desires and emotions and stimulate good thoughts and feelings. Continuous struggle to keep the modifications or thoughts of the mind perfectly restrained is practice.
A mind is the result of the past thinking. It is constantly being modified by present thinking. It is material. It is made up of subtle matter. It borrows light form Atman or Soul. Train your mind. Avoid dissipation of the mental forces in mind — wandering, daydreaming and badly directed and unorganised thinking. Self-discipline must begin with the mind first. The practice of Sama (control of mind) comes first and then comes Dama (control of senses). The subconscious mind is a sort of vast storeroom underneath the conscious mind. The subconscious mind plays an important part in the psychological life of man. Your distractions, pulls and cravings emanate from the subconscious.
The conscious mind co-operates with and never condemns the subconscious. This world is full of wonders, but nothing is more wonderful than mind. Have always a background of good divine thoughts. Let not your mind stay idle. Silence of the heart, silence of the mind is better than the silence of the tongue. Man’s mind cannot rest until it finds rest in God. The mind is born of bliss. So it tries to attain happiness. It is always seeking to attain Brahman or the Absolute who is an embodiment of bliss. The mind requires Being or Reality.
(pgs. 27-28, Conquest of Mind)