Bhagwad Gita
Chapter 13, Verse 12
अध्यात्मज्ञाननित्यत्वं तत्त्वज्ञानार्थदर्शनम्।एतज्ज्ञानमिति प्रोक्तमज्ञानं यदतोन्यथा।।13.12।।
Constancy in Self-knowledge, the perception of the end of true knowledge—this is declared to be knowledge, and what is opposed to it is ignorance.