Srimad Bhagavatam Canto 07, Chapter 07, Text 10

SB 7.7.10

sri-narada uvaca
ayam niskilbisah saksan
 maha-bhagavato mahan
tvaya na prapsyate samstham
 anantanucaro bali
 
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
Narada Muni replied: The child within this woman’s womb is faultless and sinless. Indeed, he is a great devotee, a powerful servant of the Supreme Personality of Godhead. Therefore you will not be able to kill him.
 
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
There have been many instances in which demons or nondevotees have attempted to kill a devotee, but they have never been able to destroy a great devotee of the Supreme Personality of Godhead. The Lord promises in Bhagavad-gita (9.31), kaunteya pratijanihi na me bhaktah pranasyati. This is a declaration by the Supreme Personality of Godhead that His devotee cannot be killed by demons. Prahlada Maharaja is the vivid example of the truth of this promise. Narada Muni told the King of heaven, “It would be impossible for you to kill the child, even though you are demigods, and certainly it would be impossible for others.”
Srimad Bhagavatam Canto 07, Chapter 07, Text 09
Srimad Bhagavatam Canto 07, Chapter 07, Text 11