Chapter 18 · Liberation through Renunciation · Krishna said
Bhagavad Gita 18.42 — Qualities of a brahmin
शमो दमस्तपः शौचं क्षान्तिरार्जवमेव च। ज्ञानं विज्ञानमास्तिक्यं ब्रह्मकर्म स्वभावजम् ॥
śamo damastapaḥ śaucaṃ kṣāntirārjavameva ca | jñānaṃ vijñānamāstikyaṃ brahmakarma svabhāvajam ||
Meaning
Calmness, self-control, austerity, purity, patience, honesty, knowledge, wisdom from experience and faith in God are the natural duties of a brahmin.