Bhagavad Gita 18.44
Agriculture, the protection of cows, and trade are the duties of a trader, in accordance with his nature. The duty of a servant is to serve, which also agrees with his nature.
कृषिगौरक्ष्यवाणिज्यं वैश्यकर्म स्वभावजम्।परिचर्यात्मकं कर्म शूद्रस्यापि स्वभावजम्॥kṛṣigaurakṣyavāṇijyaṃ vaiśyakarma svabhāvajam|paricaryātmakaṃ karma śūdrasyāpi svabhāvajam||
English translation (above): Shri Purohit Swami (1935), public domain. Sanskrit text via github.com/gita/gita (Unlicense).