For removal of those (obstacles and accompanying symptoms) the practice of concentration on one principle (is to be done).
Yoga Sutras (1:32)
Worldly pleasures intensify the desire for enjoying greater pleasures. Hence, the mind of worldly people is very restless. There is no satisfaction and mental peace. The mind can never be satisfied, whatever amount of pleasure you may store up for it. The more it enjoys the pleasures, the more it wants them. So, people are exceedingly troubled and bothered by their own minds. They are tired of their minds. In order to remove these botherations and troubles, the rishis thought it best to deprive the mind of all sensual pleasures. When the mind has been concentrated or made extinct, it cannot pinch one to seek further pleasure. All botherations and troubles are removed forever and the person attains real peace.
The mind is drawn towards various objects. There is dissipation of mental energy or the powers of the mind, in various directions. The rays of the mind are like the rays of light, scattered in the case of worldly-minded persons. When the rays of the mind are scattered over diverse objects, you get pain. When the rays are gathered and concentrated by practice, the mind becomes concentrated and you get ananda, happiness, from within.
When you see your dear friend after six years, the ananda that you get is not from the person, but from within yourself. The mind becomes concentrated for the time being and you get happiness from within your own self. When you are in Kashmir and enjoying the picturesque scenery of Muttan, Gulmarg, Sonamarg, Chashmashahi and Anantanag, your mind will be suddenly upset by shock if you receive a telegram which brings the unhappy tidings of the untimely demise of your only son. The scenery will no longer interest you. It has have lost its charm for you. There is no more attention. There is depression. It is concentration and attention that gives you pleasure in sightseeing.
For purposes of concentration, you will have to gather the scattered rays of the mind patiently through vairagya and abhyasa, non-attachment and sustained practice, through tyaga and tapas, renunciation and austerity, and then march boldly with indefatigable energy towards God or Brahman. Through constant sadhana, the mind must be checked from externalizing. It must be made to move towards Brahman, its original home. When the mental rays are concentrated, illumination begins.
The mind is compared to quicksilver, because its rays are scattered over various objects. It is compared to a monkey, because it jumps from one object to another object. It is compared to moving air, because it is unstable and fickle. It is compared to a furious, rutting elephant, because of its passionate impetuosity. The mind is known by the name Great Bird, because it jumps from one object to another object just as a bird jumps from one twig to another, from one tree to another. Raja yoga teaches us how to concentrate the mind and then how to ransack the innermost recesses of our own mind.
Kshipta, mudha, vikshipta, ekagra and niruddha are the five yogic bhumikas. The chitta or mind manifests itself in five different forms. In the kshipta state, the rays of the mind are scattered on various objects. It is restless and jumps from one object to another. In the mudha state, the mind is dull and forgetful. Vikshipta is the gathering mind. It is occasionally steady and at other times distracted. By practice of concentration, the mind struggles to gather itself. In the ekagra state it is one-pointed. There is only one idea present in the mind. The mind is under perfect control in the niruddha state. To stop the modifications of the mind dharana, concentration, is practised
By manipulating the mind, you will be able to bring it under your control, make it work as you like and compel it to concentrate its powers as you desire. He who has learnt to manipulate the mind will get the whole of Nature under his control.
There is no limit to the power of the human mind. The more concentrated it is, the more power is brought to bear on one point. A scientist concentrates his mind and invents many things. Through concentration, he opens the layers of the gross mind and penetrates deeply into higher regions of the mind and obtains deeper knowledge. He concentrates all the energies of his mind into one focus and throws them out upon the materials he is analysing and so finds out their secrets.
Some medical students leave the medical college soon after joining it as they find it disgusting to wash the pus in ulcers and dissect dead bodies. They make a serious blunder. After studying pathology, medicine, operative surgery, morbid anatomy, bacteriology, the course will be very interesting in the final year.
Many spiritual aspirants leave the practice of concentration of mind after some time as they find it difficult to practise. They also make a grave mistake like the medical students. In the beginning of practice, when you struggle to get over the body-consciousness, it will be troublesome. It will be a physical wrestling. The emotions and sankalpas, ideas and fancies, will be abundant. In the third year of practice, the mind will be cool, pure and strong and you will derive immense joy. The sum total of pleasures of the whole world is nothing when compared to the ananda or bliss derived from meditation.
Do not give up the practice at any cost. Plod on and persevere. Have patience, cheerfulness, and tenacity. You will succeed eventually. Never despair. Find out by serious introspection the various impediments that act as stumbling blocks in your concentration and remove them with patience and efforts one by one. Do not allow new sankalpas and new vasanas, desires, to crop up. Nip them in the bud through viveka and vichara, discrimination and reflection.
Know that you are progressing in yoga and sattwa is increasing, when you are always cheerful, when the mind is even and concentrated.