Truly, nothing here is as purifying as knowledge. That, the perfected in yoga, attains by themselves in their Self with time.

Superiority of knowledge. Na hi sadṛśam — nothing equal — indicates absolute uniqueness.

Pavitram — purifying — applies to jñāna because it dissolves ignorance, root of impurity. Yoga-saṃsiddhaḥ — the perfected in yoga — attains svayam — by themselves — in ātmani — their own Self — kālena — with time. Knowledge is self-revealed when practice matures.