Bhagavadgita 6.21

6.21

sukham ātyantikaṃ yat tad buddhigrāhyam atīndriyam
vetti yatra na caivāyaṃ sthitaś calati tattvataḥ

That devotion which destroys (all) misery is his, who takes due food and exercise, who toils duly in all works, and who sleeps and awakes (in) due (time). When (a man's) mind well restrained becomes steady upon the self alone, then he being indifferent to all objects of desire, is said to be devoted. As a light standing in a windless (place) flickers not, that is declared to be the parallel for a devotee, whose mind is restrained, and who devotes his self to abstraction. That (mental condition), in which the mind restrained by practice of abstraction, ceases to work; in which too, one seeing the self by the self, is pleased in the self; in which one experiences that infinite happiness which transcends the senses, and which can be grasped by the understanding only; and adhering to which, one never swerves from the truth; acquiring which, one thinks no other acquisition higher than it; and adhering to which, one is not shaken off even by great misery; that should be understood to be called devotion in which there is a severance of all connexion with pain. That devotion should be practised with steadiness and with an undesponding heart. Abandoning, without exception, all desires, which are produced from fancies, and restraining the whole group of the senses on all sides by the mind only, one should by slow steps become quiescent, with a firm resolve coupled with courage; and fixing his mind upon the self, should think of nothing.