Wisdom from the Bhagavad Gita 21

10. The Yogi should constantly practice concentration of the heart, retiring into solitude, alone, with the mind and body subdued, and free from hope and possession. 

11. Having in a cleanly spot established his seat, firm, neither too high nor too low, made of a cloth, a skin, and Kusha-grass, arranged in consecution: 

12. There, seated on that seat, making the mind one-pointed and subduing the action of the imaging faculty and the senses, let him practice Yoga for the purification of the heart.

13. Let him firmly hold his body, head and neck erect and still, with the eye-balls fixed, as if gazing at the tip of his nose, and not looking around. 

14. With the heart serene and fearless, firm in the vow of a Brahmachâri, with the mind controlled, and ever thinking of Me, let him sit in Yoga having Me as his supreme goal. 

15. Thus always keeping the mind steadfast, the Yogi of subdued mind attains the peace residing in Me—the peace which culminates in Nirvâna, in Moksha (Release). 

16. Success in Yoga is not for him who eats too much or too little—nor, O Arjuna, for him who sleeps too much or too little. 

17. To him who is temperate in eating and recreation, in his effort for work, and in sleep and wakefulness, Yoga becomes the destroyer of misery. 

18. When the completely controlled mind rests serenely in the Self alone, free from longing after all desires, then is one called steadfast, in the Self. 

19. "As a lamp in a spot sheltered from the wind does not flicker"—even such has been the simile used for a Yogi of subdued mind, practicing concentration in the Self.

—Bhagavad Gita, 6:10-19