SB 4.14.10
aher iva payah-posah
posakasyapy anartha-bhrt
venah prakrtyaiva khalah
sunitha-garbha-sambhavah
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
The sages began to think within themselves: Because he was born from the womb of Sunitha, King Vena is by nature very mischievous. Supporting this mischievous king is exactly like maintaining a snake with milk. Now he has become a source of all difficulties.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Saintly persons are generally aloof from social activities and the materialistic way of life. King Vena was supported by the saintly persons just to protect the citizens from the hands of rogues and thieves, but after his ascendance to the throne, he became a source of trouble to the sages. Saintly people are especially interested in performing sacrifices and austerities for the advancement of spiritual life, but Vena, instead of being obliged because of the saints’ mercy, turned out to be their enemy because he prohibited them from executing their ordinary duties. A serpent who is maintained with milk and bananas simply stores poison in his teeth and awaits the day to bite his master.