न हि ज्ञानेन सदृशं पवित्रमिह विद्यते। तत्स्वयं योगसंसिद्धः कालेनात्मनि विन्दति ॥

na hi jñānena sadṛiśhaṁ pavitramiha vidyate tatsvayaṁ yogasansiddhaḥ kālenātmani vindati

Verily there is no purifier in this world like wisdom; he that is perfected in yoga finds it in the Self in due season.

In plain words: Krishna says nothing in this world cleanses a person like wisdom does. A person who has mastered yoga, the practice of uniting with God, will find this wisdom inside himself when the time is right.