Mahabharata 13.131.58

एतत्ते सर्वमाख्यातं यथा शूद्रो भवेद्द्विजःब्राह्मणो वा च्युतो धर्माद्यथा शूद्रत्वमाप्नुते

etatte sarvamākhyātaṃ yathā śūdro bhaveddvijaḥbrāhmaṇo vā cyuto dharmādyathā śūdratvamāpnute

Our plain-language meaning of this verse is waiting for scholar review.