Mahabharata 13.109.13

चतुर्थभक्तक्षपणं वैश्यशूद्रे विधीयतेत्रिरात्रं न तु धर्मज्ञैर्विहितं ब्रह्मवादिभिः

caturthabhaktakṣapaṇaṃ vaiśyaśūdre vidhīyatetrirātraṃ na tu dharmajñairvihitaṃ brahmavādibhiḥ

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