The inner control of thoughts is a further development once the poise of the witness consciousness has been attained. As the seeker observes the thoughts, he can also determine their effect in the being, and see if they lead to uplifting, widening, and harmonizing results, or whether they shrink the being back down into the ego-consciousness with all of its turmoil, disruptions and limitations. For the yogic practitioner the issue is not one of an artificial external moral or ethical code, but rather, the consciousness-impact of the thoughts that are permitted to act within the being.
Sri Aurobindo related the way he was introduced to the idea of observing and rejecting the thoughts that tried to enter, and indicated that at the end of 3 days he was able to achieve silence of the mind, which in turn opened up the receptivity to higher states of receptivity and awareness. He was asked to see that the thoughts came from outside and as they tried to enter, he should reject them. This somewhat strenuous approach is not suited for everyone, and most teachers recommend simply observing without reacting and letting them glide through without being grabbed on and followed. Either way, the active or the passive means, can lead to the end result of bringing quiet, silent receptivity to the mind. The Mother recommends an approach here in her discussion of the Dhammapada verses relating to the achievement of a state of happiness rather than suffering.
In the book Commentaries on the Dhammapada, The Mother provides insight into a number of verses from this classical Buddhist text. The Dhammapada states: ” ‘He has insulted me, he has beaten me, he has humiliated me, he has robbed me.‘ Those who do not nourish thoughts such as these foster no hatred.”
The Mother observes: “This is the counterpart of what we read the other day. But note that this concerns only thoughts that generate resentment. It is because rancour, along with jealousy, is one of the most widespread causes of human misery. … But how to avoid rancour? A large and generous heart is certainly the best means, but that is not within the reach of all. Controlling one’s thought may be of more general use.”
“Thought-control is the third step of our mental discipline. Once the enlightened judge of our consciousness has distinguished between useful and harmful thoughts, the inner guard will come and allow to pass only approved thoughts, strictly refusing admission to all undesirable elements. … With a commanding gesture the guard will refuse entry to every bad thought and push it back as far as possible. … It is this movement of admission and refusal that we call thought-control and this will be the subject of our meditation tonight.”
Sri Aurobindo and The Mother, Living Within: The Yoga Approach to Psychological Health and Growth, Disturbances of Mind, Unruly and Perturbing Thoughts, pp. 35-43