Bhagavad Gita 13.12

अध्यात्मज्ञाननित्यत्वं तत्वज्ञानार्थदर्शनम् |
एतज्ज्ञानमिति प्रोक्तमज्ञानं यदतोऽन्यथा

Translation

constancy in spiritual knowledge; and philosophical pursuit of the Absolute Truth—all these I declare to be knowledge, and what is contrary to it, I call ignorance.