Bhagavad Gita: Abandoning all attachment to the results of activities, ever satisfied and independent (Bhagavad Gita, Text 20, Ch 4, Transcendental Knowledge)

Tyaktva karma-phalasangam

nitya-trpto nirasrayah

karmany abhipravrtto'pi

naiva kincit karoti sah

(Bhagavad Gita, Text 20, Ch 4, Transcendental Knowledge)

Meaning: Abandoning all attachment to the results of his activities, ever satisfied and independent, he performs no fruitive action, although engaged  in all kinds of undertakings.