If a pebble in our shoe torments us, we expel it. Once the matter is understood, it is just as easy to expel an intruding and obnoxious thought from the mind. Thoughts are the sources of all actions - they are real karma, real action. If, right at the beginning, you can root out all evil thoughts, you will not do any evil actions. You will be free from misery and anxiety.
Watch the thoughts with vigilance. Once the tossing of the mind vanishes, the mind will be very calm and you will get good meditation. Free yourself from the clutches of the mind, and liberation will come by itself. Those who have even a little control over their thoughts and speech will have a calm, serene, beautiful face, a sweet voice and brilliant, lustrous eyes.
Conserve all mental energy. Use it for spiritual purposes. Do not store useless information in your brain. Learn to unmind the mind. Then only you can fill the mind with divine thoughts. As all the dissipated mental rays are collected you will gain new mental strength. Useless thoughts impede your spiritual growth; obnoxious thoughts are stumbling blocks to spiritual advancement.
In untrained persons four or five kinds of thoughts occupy the mind at one time. These may be thoughts of the household, of business, of the office, of the body and so on. If you watch carefully you will see that many thoughts are inconsistent and that the mind wanders aimlessly.
Entertain only thoughts that are useful and helpful. These are the stepping stones to all spiritual progress. Every thought must be of a constructive nature; it must be positive and definite. Mental images must be well-defined. Every thought must bring peace and comfort to others and never bring pain or unhappiness. Then, you are a blessed soul on earth.
Always watch your mind. Be vigilant. Be alert. Do not allow waves of irritability, jealousy, anger, hatred and lust to arise in the mind. These are the enemies of meditation, peace and wisdom. Suppress them at once by entertaining sublime thoughts. Evil thoughts which have already arisen may be destroyed by originating and maintaining good thoughts, by repeating any mantra, by doing any good actions, by abstracting the mind and by enquiring, "Who am I?" or by will-force.