Yoga Sūtra Chapter Four verse 8

ततः तद्विपाकानुग्णानामेवाभिव्यक्तिः वासनानाम् ॥८॥

tataḥ tat-vipāka-anuguṇānām-eva-abhivyaktiḥ vāsanānām ||8||

From that,
indeed the manifestation of latent impressions
that have similar qualities to the result.

tatas - hence, from thattat - that, thisvipāka - results; effect, result, consequence; ripening, maturing; digestion; conversion of food into a state for assimilationanuguṇa - having similar qualitieseva - indeed, truly, really; thus; so, just so, exactly soabhivyakti - manifestation; distinctionvāsanā - latent impressions; the impression of anything remaining unconsciously in the mind; the act of perfuming

Commentaries and Reflections

Commentary by T Krishnamacharya:

Commentary by TKV Desikachar:

“Nothing destroys Vāsana,
only they become ineffective.”

Commentary by S Ramaswami:

“Saṃskāra produce new births. The previous birth carries forward Vāsana. Thus Saṃskāra or habits are always in this birth.
Vāsana are latent tendencies that come from a previous birth or from early in this birth. When the conditions are right they arise.
They are otherwise so subtle they cannot be known.
So Saṃskāra are of two types, those that have manifested and give impetus for a new birth and those that have come forward as Vāsana.
Thus Vāsana only go when the pot has been emptied, scoured and then heated.
Discrimination alone removes Vāsana.
You must create a situation where the Vāsana are not able to sprout until you are able to remove them by the appropriate action.
Thus this Sūtra takes up the idea of why Vāsana works in three states and not in the fourth, that of the Yogi.
Karma is of three types: Saṃcita, Kriyamāṇa, and Prārabdha.
Saṃskāra is the last type or that which has already started and is giving fruit in this Janma. Thus Saṃskāra relate to the experiences in this life.
When Saṃskāra come forward from one Janma to another in an individual they are felt as Vāsana. These Vāsana manifest and operate through memory.
Only those Vāsana consistent with this birth manifest themselves. Saṃskāra are a storehouse but only those appropriate to this Janma manifest or come forward. Thus the individual contains the Vāsana of many, many births. In this Janma only those Vāsana relevant to this birth and situation emerge.
It is said therefore, that one takes birth in a human form because of the Vāsana of the human being, being within the individual’s memory.
The internal environment affects one, so the appropriate Vāsana emerge while the others continue to be submerged.
The idea here is that one can either go on and on in Saṃskāra or through Yoga remove oneself from it.”

Commentary by Paul Harvey:

Vāsanā is an unconscious motivation, directed towards
satisfying a physiological or psychological need.”