The Compendium of Caraka 1.5.104

1.5.104

bhavati cātra --- vṛttyupāyānniṣeveta ye syurdharmāvirodhinaḥ/
śamamadhyayanaṃ caiva sukhamevaṃ samaśnute//

And here it is said:
One should pursue means of livelihood that do not conflict with righteousness,
and practice tranquility and study; thus one attains happiness.