Srimad-Bhagavatam: Canto 10 - Chapter 1 - Verse 33
Sanskrit:
नागपत्न्य ऊचु:न्याय्यो हि दण्ड: कृतकिल्बिषेऽस्मिं-स्तवावतार: खलनिग्रहाय ।रिपो: सुतानामपि तुल्यदृष्टि-र्धत्से दमं फलमेवानुशंसन् ॥ ३३ ॥
ITRANS:
nāga-patnya ūcuḥnyāyyo hi daṇḍaḥ kṛta-kilbiṣe ’smiṁstavāvatāraḥ khala-nigrahāyaripoḥ sutānām api tulya-dṛṣṭirdhatse damaṁ phalam evānuśaṁsan
Translation:
The wives of the Kāliya serpent said: The punishment this offender has been subjected to is certainly just. After all, You have incarnated within this world to curb down envious and cruel persons. You are so impartial that You look equally upon Your enemies and Your own sons, for when You impose a punishment on a living being You know it to be for his ultimate benefit.