SB 10.16.34

anugraho ’yaṁ bhavataḥ kṛto hi no
 daṇḍo ’satāṁ te khalu kalmaṣāpahaḥ
yad dandaśūkatvam amuṣya dehinaḥ
 krodho ’pi te ’nugraha eva sammataḥ
Synonyms: 
anugrahaḥ — mercy; ayam — this; bhavataḥ — by You; kṛtaḥ — done; hi — indeed; naḥ — to us; daṇḍaḥ — punishment; asatām — of the evil; te — by You; khalu — indeed; kalmaṣa-apahaḥ — the dispelling of their contamination; yat — because; dandaśūkatvam — the condition of appearing as a serpent; amuṣya — of this Kāliya; dehinaḥ — the conditioned soul; krodhaḥ — anger; api — even; te — Your; anugrahaḥ — as mercy; eva — actually; sammataḥ — is accepted.
Translation: 
What You have done here is actually mercy for us, since the punishment You give to the wicked certainly drives away all their contamination. Indeed, because this conditioned soul, our husband, is so sinful that he has assumed the body of a serpent, Your anger toward him is obviously to be understood as Your mercy.
Purport: 

Śrīla Madhvācārya points out in this connection that when a pious person suffers in this world, he realizes, “The punishment the Supreme Lord is meting out to me is actually His causeless mercy.” Envious persons, however, even after being punished by the Lord for their purification, continue to envy Him and be resentful, and this attitude is the reason for their continued failure to understand the Absolute Truth.