Srimad Bhagavatam Canto 10, Chapter 01, Text 37

SB 10.1.37

sri-vasudeva uvaca
slaghaniya-gunah surair
bhavan bhoja-yasaskarah
sa katham bhaginim hanyat
striyam udvaha-parvani
 
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
Vasudeva said: My dear brother-in-law Kamsa, you are the pride of your family, the Bhoja dynasty, and great heroes praise your qualities. How could such a qualified person as you kill a woman, your own sister, especially on the occasion of her marriage?
 
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
According to Vedic principles, a brahmana, an old man, a woman, a child or a cow cannot be killed under any circumstances. Vasudeva stressed that Devaki was not only a woman but a member of Kamsa’s family. Because she was now married to Vasudeva, she was para-stri, another man’s wife, and if such a woman were killed, not only would Kamsa be implicated in sinful activities, but his reputation as king of the Bhoja dynasty would be damaged. Thus Vasudeva tried in many ways to convince Kamsa in order to stop him from killing Devaki.
Srimad Bhagavatam Canto 10, Chapter 01, Text 36
Srimad Bhagavatam Canto 10, Chapter 01, Text 38