Chapter 4 · Knowledge and Renunciation of Action · Krishna said
Bhagavad Gita 4.38 — Nothing purifies like knowledge
न हि ज्ञानेन सदृशं पवित्रमिह विद्यते। तत्स्वयं योगसंसिद्धः कालेनात्मनि विन्दति ॥
na hi jñānena sadṛśaṃ pavitramiha vidyate | tatsvayaṃ yogasaṃsiddhaḥ kālenātmani vindati ||
Meaning
Nothing in this world purifies like knowledge. One who is perfected in yoga finds it within, in the self, in due time.