The background of thought of a Manradi is about his money. His mind is always on the safe. He plans, speculates and schemes as how to increase his money in the bank from one lakh to two lakhs. The background of thought of a young man is about his wife. The background of thought of a doctor is about his patients, dispensary and drugs. The background of thought of a lawyer is about his clients, courts and rulings of the High court. The background of thought of an old grandmother is about her grand-children. The vast majority of people indulge in thoughts of jealousy and hatred and these thoughts form their background.
But the background of thought of a Bhakta is about his Ishta-Devata. A devotee of Lord Krishna always thinks of Krishna with flute in hand. He has a concrete background. A Vedantin or a student of Yoga has an abstract background. He meditates on abstract ideas. A Sattvic background keeps the mind always pure and takes the devotee to the goal. The mental image of Lord Krishna destroys all other worldly thoughts. A sacred background of thought either concrete or abstract is a valuable spiritual asset for a man. A habit to think of the image is formed by constant thinking of one’s Ishta Devata. Even in the office when you leave the pen on the table, the mind through the force of habit will at once move to the background of thought and think of the picture of Lord Krishna. Even in dream you will have vision of Lord Krishna only. The greater the Sadhana, the stronger the background of thought of the mental image.
The image leaves a definite impression on the mind. This is called Samskara. If this impression is repeated very often, a tendency or habit is formed in the mind. That is the reason why the aspirant is asked to repeat the Mantra several lakhs of times. A man can shape his mind for good or bad. It depends upon the nature of food he gives to the mind. Every thought produces a definite change in the substance of the brain also.
One has to create a Sattvic background of thought through continued struggle. The mind will run back to its old ruts and manufacture images of worldly objects. The Sadhaka will have to bring back again and again the mind to the Sattvic background of thought that he has developed. The struggle will be keen in the beginning. Later on the mind will quietly rest in the spiritual background of thought.
Excerpts from “Practice of Bhakti Yoga” by Swami Sivananda