The Yoga of Liberation by Renunciation

Krishna explains the duties of brahmanas. 'Śamo damas tapaḥ śaucaṁ kṣāntir ārjavam eva ca'—control of mind (śamaḥ), control of senses (damaḥ), austerity (tapaḥ), purity (śaucam), forbearance (kṣāntiḥ), straightforwardness (ārjavam). 'Jñānaṁ vijñānam āstikyam brāhmaṇa-karma svabhāva-jam'—knowledge (jñānam), wisdom (vijñānam), faith (āstikyam)—these constitute the duty of brahmanas (brāhmaṇa-karma), born of their nature (svabhāva-jam). These are sattvic duties: qualities of knowledge, wisdom, self-control, purity, and faith. Brahmanas are those whose nature inclines toward knowledge, teaching, contemplation, and spiritual guidance. Their duty is to cultivate wisdom, control their mind and senses, practice austerity, maintain purity, and have faith. This is not about birth—it's about natural qualities and inclinations.