Chapter 18 · verse 41 · gita.yoga.org

Bhagavad Gita 18.41

ब्राह्मणक्षत्रियविशां शूद्राणां च परंतप।कर्माणि प्रविभक्तानि स्वभावप्रभवैर्गुणैः

Of Brahmanas, Kshatriyas, Vaisyas, and Sudras, O Arjuna, the duties are distributed according to the qualities born of their own nature.