tapaḥ sutaptaḿ kim anena pūrvaḿ
nirasta-mānena ca māna-dena
dharmo 'tha vā sarva-janānukampayā
yato bhavāḿs tuṣyati sarva-jīvaḥ
tapah -- austerity; su-taptam -- properly performed; kim -- what; anena -- by this Kaliya; purvam -- in previous lives; nirasta-manena -- being free from false pride; ca -- and; mana-dena -- giving respect to others; dharmah -- religious duty; atha va -- or else; sarva-jana -- to all persons; anukampaya -- with compassion; yatah -- by which; bhavan -- Your good self; tushyati -- is satisfied; sarva-jivah -- the source of life for all beings.
In this regard Srila Prabhupada comments in his Krishna, the Supreme Personality of Godhead, Volume 1, Chapter Sixteen: "The Naga-patnis confirm that one cannot come in contact with Krishna without having executed pious activities in devotional service in one's previous lives. As Lord Caitanya advised in His Sikshashtaka, one has to execute devotional service by humbly chanting the Hare Krishna mantra, thinking oneself lower than the straw in the street and not expecting honor for oneself but offering all kinds of honor to others. The Naga-patnis were astonished that, although Kaliya had the body of a serpent as the result of grievous sinful activities, at the same time he was in contact with the Lord to the extent that the Lord's lotus feet were touching his hoods. Certainly this was not the ordinary result of pious activities. These two contradictory facts astonished them."