Kathoupanishd 2-III-17

 Purusha of the size of a thumb, the inner Self, is ever seated in the heart of all living beings. One should, with steadiness, separate Him from one’s own body as stalk from the Munja grass. One should know Him as pure and immortal; one should know Him as pure and immortal. 2-III-18. Nachiketas then, having acquired this knowledge imparted by Death, as also the instructions on Yoga in entirety, attained Brahman having become dispassionate and deathless. So does become any one else also who knows the inner Self thus.