Sanskrit
शमो दमस्तपः शौचं क्षान्तिरार्जवमेव च । ज्ञानं विज्ञानमास्तिक्यं ब्रह्मकर्म स्वभावजम् ॥ ४२ ॥
śamo damas tapaḥ śaucaṃ kṣāntir ārjavam eva ca jñānaṃ vijñānam āstikyaṃ brahma-karma svabhāvajam
Translation
Serenity, self-restraint, austerity, purity, forgiveness and also uprightness, wisdom, knowledge, belief in God, are the Brâhmana duty, born of his own nature.
Annie Besant · The Bhagavad-Gita, translated by Annie Besant (4th ed., 1922) — Wikisource · Public Domain
Explanation
The Brahmana’s list — serenity, self-restraint, austerity, purity, forgiveness, uprightness, wisdom, knowledge, faith — reads less like a job description than a sattva-dominant temperament profile, echoing the sattvic catalogues already run in chapters 14, 16, and 17. If svabhava really means guna-composition rather than bloodline, this is the clearest evidence for it in the chapter; the text simply never settles whether that composition is fixed by birth or genuinely open to whoever cultivates these qualities.