अध्यात्मज्ञाननित्यत्वं तत्त्वज्ञानार्थदर्शनम्। एतज्ज्ञानमिति प्रोक्तमज्ञानं यदतोन्यथा ॥

adhyātma-jñāna-nityatvaṁ tattva-jñānārtha-darśhanam etaj jñānam iti proktam ajñānaṁ yad ato ’nyathā

Constancy in the wisdom of the Self, understanding of the object of essential wisdom; that is declared to be the Wisdom; all against it is ignorance.

In plain words: Krishna finishes his list of what true wisdom is. It means staying steady in knowing your true Self and understanding what real knowledge points to. Anything opposed to this is ignorance.