Bhagavad Gita Chapter 4.38
na hi jñānena sadṛśaḿ
pavitram iha vidyate
tat svayaḿ yoga-saḿsiddhaḥ
kālenātmani vindati
Translation
In this world, there is nothing so sublime and pure as transcendental knowledge. Such knowledge is the mature fruit of all mysticism. And one who has become accomplished in the practice of devotional service enjoys this knowledge within himself in due course of time.