Shraddhadipa 2.74

Śrāddhadīpa 2.74

śudhyed vipro daśāhena dvādaśāhena bhūmipaḥ
vaiśyaḥ pañcadaśāhena śūdro māsena śuṣyati
śaucāśaucaṃ prakurvīran śūdravadvarṇasaṅkarāḥ