Yoga Sutra - Samādhi Pada 1.50
The saṁskāras born out of that [truth-bearing wisdom] obstruct other saṁskāras [from emerging].
Patañjali here states that the truth-bearing wisdom, ṛtambharā–jñāna of I.48, produces a certain type of saṁskāra of its own. Evidently, these pratibandhī or blocking saṁskāras are effectively the virāma–pratyaya, the thought of terminating all thoughts, of I.18. Such truth-bearing wisdom saṁskāras, Vyāsa hastens to add, do not provoke the mind into vṛtti activity or activate as thought or in any way agitate the citta, which would be counterproductive to the goal of yoga. Their function is solely to block the activation and emergence of other conventional saṁskāras that lie dormant in the saṁskāric deposit of the citta. When these conventional saṁskāras, which produce mundane thoughts and ideas—the citta-vṛtti—are blocked, samādhi is enhanced, says Vyāsa. Samādhi, in turn, produces beneficial saṁskāras of wisdom, or discrimination, which further block the conventional saṁskāras and are in turn deposited in the citta. These then are activated and further enhance samādhi, triggering more saṁskāras of wisdom, and the cycle goes on, although the more wisdom saṁskāras that are deposited, the more the citta is transformed, and the more readily the yogī can enter into and maintain samādhi states. These beneficial saṁskāras (nirodha–saṁskāras) have been compared to a thorn used to extract another thorn, which are then both discarded.
This is because wisdom, or discrimination, is still a function of citta, says Vyāsa, and therefore produces its saṁskāras just as all activities of citta are bound to do. So although it, too, must ultimately be bypassed when its function is served, the conventional activities of the mind must first come to a halt by the rise of discrimination. But the wisdom saṁskāras born of samādhi do not impel the mind to activity; rather they destroy the conventional saṁskāras and make them impotent. When this happens, the ability of the mind to produce its citta-vṛtti effects is curtailed, and the goal of yoga achieved. The wisdom or discriminatory saṁskāras reveal the distinction between the puruṣa and prakṛti, while the conventional saṁskāras operate under ignorance, defined in II.5 as the failure to distinguish between the self and the nonself, that is, between the puruṣa and its coverings of body and mind. When discrimination arises, this illusion is destroyed; therefore, the wisdom saṁskāras are indispensable. Vijñānabhikṣu describes these truth-bearing saṁskāras, these saṁskāras of discernment, as being of different strengths, perhaps, in resonance with I.22, in accordance with the intensity of samādhi, hence the need to reinforce them by the cycle outlined by Vyāsa.
Vācaspati Miśra states that there are only two possibilities for the mind: Either it pursues the objects of the senses, or it cultivates discrimination; put differently, it can be used either for enjoyment or for liberation, as Patañjali notes in II.18. This difference in how the mind is put to use reflects the difference between the kliṣṭa, detrimental, and akliṣṭa, nondetrimental, vṛttis of I.5. The inclination of the mind to aspire after worldly objects of enjoyment occurs only as long as it does not experience lucidity and discriminative awareness of reality, which ultimately means perceiving the distinction between puruṣa and prakṛti. As will be discussed, when such discrimination arises, ignorance is destroyed and thus the deposit of karma and the afflictions of the mind are also destroyed, and the tendency of the mind to seek external enjoyment comes to an end. Rāmānanda Sarasvatī states that upon the rise of discrimination, the mind becomes disgusted with sensual experience and turns toward the self. In this vein, Hariharānanda redirects attention to sūtra I.16, where Patañjali indicates that that disinterest in the entire productivity of the guṇas, which means everything in prakṛti, results from realization of the puruṣa soul.
Vijñānabhikṣu states the Sāṅkhya and Vedāntic view here: the wisdom-bearing saṁskāras destroy only the dormant and unmanifest store of karma, and not the prārabdha–karma, the karma that has already activated. Karma exists in various stages, the exact specifications of which differ from school to school, but essentially it lies dormant awaiting later fructification, sañcita–karma, or is being accumulated by ongoing activity under ignorance in the present, sañcīyamāna; or it has already been activated and is now manifest, prārabdha. Samādhi, then, destroys all the dormant karma. However, the already activated karma of the yogī’s present experience—life span, type of body, ongoing happenings, etc. (II.13)—is terminated only upon the manifestation of the nirbīja–samādhi, the subject of the next sūtra.