Farming, cattle-herding, and trade make up the work of a vaishya, born of his own nature; and service is the work of a shudra, likewise born of his own nature.
कृषिगौरक्ष्यवाणिज्यं वैश्यकर्म स्वभावजम् | परिचर्यात्मकं कर्म शूद्रस्यापि स्वभावजम् ||१८-४४||