Shiva Purana
शूद्रकर्म यथोद्दिष्टं शूद्रो भूत्वा समाचरेत् ॥ यथावत्परिचर्य्यां तु त्रिषु वर्णेषु नित्यदा ॥ ९ ॥
Being born a Śūdra, one shall take up the duties of Śūdra as ordained, viz, the due service to the people of the other three castes.
english translation
zUdrakarma yathoddiSTaM zUdro bhUtvA samAcaret ॥ yathAvatparicaryyAM tu triSu varNeSu nityadA ॥ 9 ॥
hk transliteration by Sanscript