Mahabharata 13.131.13

क्षत्रियो वा महाभागे वैश्यो वा धर्मचारिणिस्वानि कर्माण्यपाहाय शूद्रकर्माणि सेवते

kṣatriyo vā mahābhāge vaiśyo vā dharmacāriṇisvāni karmāṇyapāhāya śūdrakarmāṇi sevate

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