A person is said to be pure in birth when he is born of a mother who has only one husband and who is of the same caste with him. Indeed, such a Brahmana, knowing the three Vedas, viz., Rich, Yajush, and Saman, endued with learning, only observant of the six duties, has been considered as deserving of gifts.
सत्कृता चैकपत्नी च जात्या योनिरिहेष्यते। ऋग्यजुः सामगो विद्वान् षट्कर्मा पात्रमुच्यते॥