Mahabharata 13.20.18

आतिथ्यं परमं कार्यं शुश्रूषा भवतस्तथासंवर्ततामित्युवाच मुनिर्मधुरया गिरा

ātithyaṃ paramaṃ kāryaṃ śuśrūṣā bhavatastathāsaṃvartatāmityuvāca munirmadhurayā girā

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