Bhagavad Gita Chapter 4, Verse 38

न हि ज्ञानेन सदृशं पवित्रमिह विद्यते | तत्स्वयं योगसंसिद्धः कालेनात्मनि विन्दति ||

na hi jñānena sadṛśaṁ pavitram iha vidyate tat svayaṁ yogasaṁsiddhaḥ kālenātmani vindati

There is nothing here as pure as knowledge. He who is perfected in yoga finds it in himself in time.

Krishna declares knowledge as the ultimate purifier—nothing in this world is as pure as knowledge. 'Na hi jñānena sadṛśaṁ pavitram iha vidyate' (nothing here is as pure as knowledge) means knowledge is the highest purifier—no material practice, no external ritual, no physical action is as purifying as understanding. The phrase 'tat svayaṁ yogasaṁsiddhaḥ kālenātmani vindati' (he who is perfected in yoga finds it in himself in time) shows that knowledge comes from within—through practice (yoga), over time (kālena), you find knowledge in yourself (ātmani). This verse emphasizes that knowledge isn't external information—it's inner wisdom that emerges through practice and time. The highest purifier isn't found outside, but discovered within through dedicated practice.