Krishna's Mercy

“The inhabitants of Vrindavana were perplexed by great difficulties because a certain portion of the Yamuna was poisoned by the chief of the reptiles [Kaliya]. The Lord chastised the snake-king within the water and drove him away, and after coming out of the river, He caused the cows to drink the water and proved that the water was again in its natural state.” (Shrimad Bhagavatam, 3.2.31)