raja-vidya raja-guhyam pavitram idam uttamam
pratyak savagamam dharmyam susukham kartum avyayam
This knowledge is the king of all wisdom, the king of all that is confidential. It is the purest and the topmost and because it gives direct perception of the self by realization it is the perfection of all religion and everlastingly joyful to perform. Bhagavad-Gita, chapter 9, verse 2