Mahabharat

siva.sh/mahabharat/vana-parva/206/12

यस तु शूद्रॊ दमे सत्ये धर्मे च सततॊत्थितः तं बराह्मणम अहं मन्ये वृत्तेन हि भवेद दविजः ।। ३-२०६-१२ ।।

sanskrit

'On the other hand, I consider a Shudra who is always adorned with virtues such as righteousness, self-restraint, and truthfulness, to be a Brahmana. A man becomes a Brahmana by his character.' ।। 3-206-12 ।।

english translation

yasa tu zUdrò dame satye dharme ca satatòtthitaH taM barAhmaNama ahaM manye vRttena hi bhaveda davijaH || 3-206-12 ||

hk transliteration by Sanscript