Chapter 13 · The Field and the Knower · Krishna said
Bhagavad Gita 13.12 — This is knowledge
अध्यात्मज्ञाननित्यत्वं तत्त्वज्ञानार्थदर्शनम्। एतज्ज्ञानमिति प्रोक्तमज्ञानं यदतोऽन्यथा ॥
adhyātmajñānanityatvaṃ tattvajñānārthadarśanam | etajjñānamiti proktamajñānaṃ yadato'nyathā ||
Meaning
constant focus on knowledge of the Self and seeing the purpose of knowing the truth — this is called knowledge. Whatever is opposite to it is ignorance.