Neither birth, nor the purificatory rites, nor learning, nor offspring, can be considered as grounds for conferring upon one the dignity of a twiceborn person Indeed, conduct is the only ground.
न योनि पि संस्कारो न श्रुतं न च संततिः। कारणानि द्विजत्वस्य वृत्तमेव तु कारणम्॥