Manusmriti

siva.sh/manusmriti/10/123

विप्रसेवैव शूद्रस्य विशिष्टं कर्म कीर्त्यते । यदतोऽन्यद् हि कुरुते तद् भवत्यस्य निष्फलम् ॥ १२३ ॥

sanskrit

The service of Brahmanas alone is declared (to be) an excellent occupation for a Sudra; for whatever else besides this he may perform will bear him no fruit.

english translation

viprasevaiva zUdrasya viziSTaM karma kIrtyate | yadato'nyad hi kurute tad bhavatyasya niSphalam || 123 ||

hk transliteration by Sanscript