BG 6.18-20
When his subdued thought is fixed on the Self, free from longing after all desirable things, then it is said, "he is harmonised." As a lamp in a windless place flickereth not, to such is likened the Yogî of subdued thought, absorbed in the yoga of the Self. That in which the mind finds rest, quieted by the practice of yoga: that in which he, seeing the Self by the Self, in the Self is satisfied;