Yoga Sutra 2.11 mental processes arising are got rid of by meditation
Sūtra II.11
Mental processes arising from them are got rid of by meditation
Mental processes from the taints are in manifest form (sthūla), and are first thinned out by the yoga of action; then they are to be got rid of by contemplation (prasaṅkhyāna), by meditation (dhyāna), until having thereby been made subtle, they are then made like scorched seeds.
(Opponent) Which are the ones then which do need practices like meditation?
(Answer) As to those which persist, though reduced to the seed state, mental processes arising from them are got rid of by meditation. Mental processes from the taints are in manifest form, and are first thinned out by the yoga of action, consisting of tapas, self-study, and devotion to the Lord, this yoga being the opponent on the level of manifestation. Then from that thinning out they are reduced to the state of seed powers, when they are to be got rid of by contemplation (prasaṅkhyāna), by meditation (dhyāna) finely developed through constancy in right vision, which meditation is their great and mighty opponent, until they have been thereby made subtle, and more than that have been made like scorched seeds, until they have been made in fact no seeds at all.
As with washing clothes, first the surface dirt is scoured off; afterwards the deeper staining is removed by efforts with special means. In the same way the surface mental processes arising from the taints are lesser obstacles, but when subtle, they are great obstacles.
What is the process like? As with washing clothes, first the surface (sthūla) dirt is scoured off and afterwards the deeper (sūkṣma, subtle) staining caused by oil and the like, is removed by efforts with special means, effective means such as alkalis; in the same way the surface (sthūla) mental processes arising from the taints are lesser obstacles which are overcome by practice of the yogic methods of tapas, self-study, devotion to the Lord, restraints and observances and the others; but when subtle, they are great obstacles to the steadiness of the light of right vision (samyagdarśana) created through the practices like tapas and self-study. They are great obstacles in view of their power as seeds.