Skandapurana 5.271.41

5.271.41

śālakairbāṃdhavāścaiva hyasatībhiḥ kulastriyaḥ ..
śūdrāstapasvinaścaiva śūdrā dharmasya sūcakāḥ ..41..

kinsmen by brothers-in-law, and noble wives by unchaste women. / Śūdras become ascetics, and śūdras proclaim righteousness;