Narasimhapurana 58.11

58.11

dāsavad brāhmaṇānāṃ ca viśeṣeṇa samācaret
ayācitaṃ pradātavyaṃ kṛṣiṃ vṛttyartham ācaret //

and especially, he should act like a servant towards brāhmaṇas; / he should give unasked, and engage in agriculture for his livelihood;