Mahabharata 8.23.32

ब्राह्मणा ब्रह्मणा सृष्टा मुखात्क्षत्रमथोरसःऊरुभ्यामसृजद्वैश्याञ्शूद्रान्पद्भ्यामिति श्रुतिःतेभ्यो वर्णविशेषाश्च प्रतिलोमानुलोमजाः

brāhmaṇā brahmaṇā sṛṣṭā mukhātkṣatramathorasaḥūrubhyāmasṛjadvaiśyāñśūdrānpadbhyāmiti śrutiḥtebhyo varṇaviśeṣāśca pratilomānulomajāḥ

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