Manusmriti
तपोबीजप्रभावैस्तु ते गच्छन्ति युगे युगे । उत्कर्षं चापकर्षं च मनुष्येष्विह जन्मतः ॥ ४२ ॥
By the power of austerities and of the seed (from which they sprang), these (races) obtain here among men more exalted or lower rank in successive births.
english translation
tapobIjaprabhAvaistu te gacchanti yuge yuge । utkarSaM cApakarSaM ca manuSyeSviha janmataH ॥ 42 ॥
hk transliteration by Sanscript