tasyāvanijya caraṇau tad-apaḥ sva-mūrdhnā
bibhraj jagad-gurutamo 'pi satāḿ patir hi
brahmaṇya-deva iti yad guṇa-nāma yuktaḿ
tasyaiva yac-caraṇa-śaucam aśeṣa-tīrtham
tasya -- his; avanijya -- washing; caranau -- the feet; tat -- that; apah -- water; sva -- His own; murdhna -- on the head; bibhrat -- carrying; jagat -- of the entire universe; guru-tamah -- the supreme spiritual master; api -- even though; satam -- of the saintly devotees; patih -- the master; hi -- indeed; brahmanya -- who favors the brahmanas; devah -- the Lord; iti -- thus called; yat -- since; guna -- based on His quality; nama -- the name; yuktam -- fitting; tasya -- His; eva -- indeed; yat -- whose; carana -- of the feet; saucam -- the bathing; asesha -- complete; tirtham -- holy shrine.
Since Lord Krishna's own lotus feet are the source of the most holy Ganges, the Lord did not have to purify Himself by bathing Narada Muni's feet. Rather, as Srila Prabhupada explains, "Lord Krishna in Dvaraka enjoyed the pastimes of a perfect human being. When, therefore, He washed the feet of the sage Narada and took the water on His head, Narada did not object, knowing well that the Lord did so to teach everyone how to respect saintly persons."