Srimad Bhagavatam Canto 04, Chapter 14, Text 31

 SB 4.14.31

hanyatam hanyatam esa
papah prakrti-darunah
jivañ jagad asav asu
kurute bhasmasad dhruvam
 
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
All the great saintly sages immediately cried: Kill him! Kill him! He is the most dreadful, sinful person. If he lives, he will certainly turn the whole world into ashes in no time.
 
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
Saintly persons are generally very kind to all kinds of living entities, but they are not unhappy when a serpent or a scorpion is killed. It is not good for saintly persons to kill, but they are encouraged to kill demons, who are exactly like serpents and scorpions. Therefore all the saintly sages decided to kill King Vena, who was so dreadful and dangerous to all human society. We can appreciate the extent to which the saintly sages actually controlled the king. If the king or government becomes demonic, it is the duty of a saintly person to upset the government and replace it with deserving persons who follow the orders and instructions of saintly persons.
Srimad Bhagavatam Canto 04, Chapter 14, Text 42
Srimad Bhagavatam Canto 04, Chapter 14 Overview