12-13. All the doors of the senses closed, the mind shut in into the heart, the life-force taken up out of its diffused movement into the head, the intelligence concentrated in the utterance of the sacred syllable OM and its conceptive thought in the remembrance of the supreme Godhead, he who goes forth, abandoning the body, he attains to the highest status.

14. He who continually remembers Me, thinking of none else, the Yogin, O Partha, who is in constant union with Me, finds Me easy to attain.

15. Having come to me, these great souls come not again to birth, this transient and painful condition of our mortal being; they reach the highest perfection.

16. The highest heavens of the cosmic plan are subject to a return to rebirth, but, O Kaunteya, there is no rebirth imposed on the soul that comes to Me (the Purushottama).

Bhagavad-Gita chap 8