Narasimhapurana 58.6

58.6

gorakṣākṛṣivāṇijyaṃ kuryād vaiśyo yathāvidhi
dānadharmaṃ yathāśaktyā guruśuśrūṣaṇaṃ tathā //

A vaiśya should engage in cattle-rearing, agriculture, and trade according to rule, / [and perform] the duty of giving gifts according to his capacity, as well as attendance upon the guru;