The thirty-first yoga sutra speaks about the flow of virtue that eradicates every kind of impurity, doubt, bias or prejudice. In this process, the highest, subjective, pure, infinite knowledge is attained. Others seem too superficial. He is, from now on continuously illuminated by the light of the infinite. Here, Patanjali speaks about a yogi, who is freed from all sufferings. His head and heart now has turned uncontaminated. The soul here is the fundamental principle; when it shines, no other light is necessary.

tada then
sarva all
avarana veil, covering, concealing, surrounding, enclosing, interrupting
mala impurities
apetasya devoid of, bereft of, deprived of, removed
jnanasya of knowledge
anahtyat because of infinity
jneyam the knowable
alpam small, little, trivial

Then, when the veils of impurities are removed, the highest, subjective, pure, infinite knowledge is attained, and the knowable, the finite, appears as trivial.

The stream of virtue extinguishes all the veils of impurities. The yogi is devoid of doubts, preconceptions and prejudices. The infinite light of the soul illumines him continuously, and his consciousness and the seer become one. For him, knowledge gained through the organs of cognition and through consciousness are insignificant compared with the infinite wisdom emanating from the soul.

This sutra describes the characteristics of the yogi who is devoid of afflicting actions. His head becomes clear and his heart clean and pure as crystal.

When the clouds dissipate, the sky becomes clear. When the sun is bright, no other light is required. When the light of the soul blazes, the yogi does not need mind or intelligence to develop knowledge.

In 11.16, Patanjali spoke of avoidable future pains. There, he had urged the sadhaka to train his intelligence through right understanding and cultivation of right action from the moment he begins yoga. In this sutra, as the consciousness has been fully matured, he cautions the yogi that if fissures are formed in the cttta, afflictions will affect him instantaneously and not at a future time.

His knowledge springs eternally from the seed of all knowledge (atman) and jnana gahga (perennial river of wisdom), and he perceives directly.