Meditation is the seventh limb according to the Yoga Sutras of sage Patanjali, the eighth being Samadhi. There are many methods of practice of concentration which leads to meditation. The purpose of meditation is to understand the real nature of the object of meditation. The mind is the instrument with which we meditate. A certain amount of the study of the nature of activities of the mind is necessary before one takes up to meditation. The existence of the mind can be found only during its activities. The thief can be found out only during the act of thieving, for at all other times he may look like an ordinary person. When the thief comes to know that the police are after him, he restricts his movements. Similarly, if you begin to study the mind, the mental processes or the activities of the mind will be reduced. There are mainly two stages of meditation. They are: (1) Constantly thinking on one object or thought, to the exclusion of all other objects and thoughts; and (2) keeping the mind free of all thoughts.
In the first stage one must concentrate one's mind on an object, or engage oneself in the repetition of the Mantra into which he is initiated by his preceptor. If one starts repeating the Mantra with concentration on the Mantra, then alone one will come to know the innumerable other thoughts which lie submerged in one's subconscious and unconscious levels of the mind and which rise to the conscious level and cause disturbance to concentration on the Mantra. When the concentration on one Mantra together with Bhava (feeling of its meaning), is increased through a long and continued practice, the mind reaches the state of meditation.
In the second stage, one should sit in a comfortable posture, close the eyes and relax all the limbs of the body from toes to the crown of the head. The ears being open, external sounds naturally will impinge on them. One should be a witness to these external sounds and also be a witness to the inner thoughts that may arise one after another in endless succession. One should not go after those inner thoughts, nor should one pay any serious attention to the external sounds. By complete relaxation in the sitting posture and by remaining as a witness of the internal and external activities of the mind, the mind will become non-objectified, after continued, unbroken practice for a long period. In the early stages care should be taken that one does not go to sleep. Sincerity, earnestness and purity of thought, word and deed, are the important factors for success in the practice of meditation.