What are the duties of a Brahmin as per the Srimad Bhagavadgita?
शमो दमस्तपश्शौचं क्षान्तिरार्जवमेव च।
ज्ञानं विज्ञानमास्तिक्यं ब्रह्मकर्म स्वभावजम् ॥ BG 18.42 ॥
शमः Pacifying sensory instincts.
दमः Controlling senses in the face of temptations.
तपः Austerities
शौचम् Purity in thought, word, and deed.
क्षान्तिः Forbearance and forgiveness.
आर्जवम् Straight-forwardness.
ज्ञानम् Learning
विज्ञानम् Wisdom and self-knowledge
आस्तिक्यम् Faith in the Supreme.
These qualities and hence duties arising from them are inborn=natural to a true Brahmin. So this is quality and not caste.
https://en.m.wikisource.org/wiki/Life_in_India/The_Brahmins
