SB 10.6.7

bāla-grahas tatra vicinvatī śiśūn
 yadṛcchayā nanda-gṛhe ’sad-antakam
bālaṁ praticchanna-nijoru-tejasaṁ
 dadarśa talpe ’gnim ivāhitaṁ bhasi
Synonyms: 
bāla-grahaḥ — the witch, whose business was to kill small babies; tatra — standing there; vicinvatī — thinking of, searching for; śiśūn — children; yadṛcchayā — independently; nanda-gṛhe — in the house of Nanda Mahārāja; asat-antakam — who could kill all demons; bālam — the child; praticchanna — covered; nija-uru-tejasam — whose unlimited power; dadarśa — she saw; talpe — (lying) on the bed; agnim — fire; iva — just like; āhitam — covered; bhasi — within ashes.
Translation: 
While searching for small children, Pūtanā, whose business was to kill them, entered the house of Nanda Mahārāja unobstructed, having been sent by the superior potency of the Lord. Without asking anyone’s permission, she entered Nanda Mahārāja’s room, where she saw the child sleeping in bed, His unlimited power covered like a powerful fire covered by ashes. She could understand that this child was not ordinary, but was meant to kill all demons.
Purport: 

Demons are always busy creating disturbances and killing. But the child lying on the bed in the house of Nanda Mahārāja was meant to kill many demons.