SB 10.6.43

nandaḥ sva-putram ādāya
 pretyāgatam udāra-dhīḥ
mūrdhny upāghrāya paramāṁ
 mudaṁ lebhe kurūdvaha
Synonyms: 
nandaḥ — Mahārāja Nanda; sva-putram ādāya — taking his son Kṛṣṇa on his lap; pretya-āgatam — as if Kṛṣṇa had returned from death (no one could even imagine that from such danger a child could be saved); udāra-dhīḥ — because he was always liberal and simple; mūrdhni — on the head of Kṛṣṇa; upāghrāya — formally smelling; paramām — highest; mudam — peace; lebhe — achieved; kuru-udvaha — O Mahārāja Parīkṣit.
Translation: 
O Mahārāja Parīkṣit, best of the Kurus, Nanda Mahārāja was very liberal and simple. He immediately took his son Kṛṣṇa on his lap as if Kṛṣṇa had returned from death, and by formally smelling his son’s head, Nanda Mahārāja undoubtedly enjoyed transcendental bliss.
Purport: 

Nanda Mahārāja could not understand how the inhabitants of his house had allowed Pūtanā to enter the house, nor could he imagine the gravity of the situation. He did not understand that Kṛṣṇa had wanted to kill Pūtanā and that His pastimes were performed by Yoga-māyā. Nanda Mahārāja simply thought that someone had entered his house and created havoc. This was Nanda Mahārāja’s simplicity.