Shiva Purana
कृत्वा च पारतापं हि करोति वचनं पुनः ॥ तेन पापेन लिंपामि नागच्छेयं पुनर्यदि ॥ ४७ ॥
After doing the crossing he makes his words again. I will be tainted by that sin if I do not go back.
english translation
kRtvA ca pAratApaM hi karoti vacanaM punaH ॥ tena pApena liMpAmi nAgaccheyaM punaryadi ॥ 47 ॥
hk transliteration by Sanscript