ब्रह्मक्षत्रियविट्शूद्रा वर्णास्त्वाद्यास्त्रयो द्विजाः ।
brahma-kṣatriya-viṭ-śūdrā varṇās tv ādyās trayo dvijāḥ |
(Yājñavalkya Smṛti: 1.10)
“Brāhmaṇa, kṣatriya, vaiśya, and śūdra are the varṇas. The first three, however, [i.e., but not the fourth, the śūdras] become twice-born (dvija).”