The Great Epic of the Bhārata dynasty 12.232.25

12.232.25

yenopāyena śakyeta saṃniyantuṃ calaṃ manaḥ |
taṃ taṃ yukto niṣeveta na caiva vicalettataḥ || 25 ||

Engaged in the observance of austere vows, the Yogin who conducts himself thus for six months, seated by himself on an isolated spot, succeeds in attaining to an equality with the Indestructible. Annihilation, extension, power to present varied aspects in the same person or body, celestial scents, and sounds, and sights, the most agreeable sensations of taste and touch, pleasurable sensations of coolness and warmth, equality with the wind, capability of understanding (by inward light) the meaning of scriptures and every work of genius, companionship of celestial damsels,--acquiring all these by Yoga the Yogin should disregard them and merge them all in the knowledge. Restraining speech and the senses one should practise Yoga during the hours after dusk, the hours before dawn, and at dawn of day, seated on a mountain summit, or at the foot of a goodly tree, or with a tree before him. Restraining all the senses within the heart, one should, with faculties concentrated, think on the Eternal and Indestructible like a man of the world thinking of wealth and other valuable possessions. One should never, while practising Yoga, withdraw one's mind from it. One should with devotion betake oneself to those means by which one may succeed in restraining the mind that is very restless. One should never permit oneself to fall away from it.