SB 4.8.39

maitreya uvāca
ity udāhṛtam ākarṇya
 bhagavān nāradas tadā
prītaḥ pratyāha taṁ bālaṁ
 sad-vākyam anukampayā
Synonyms: 
maitreyaḥ uvāca — the sage Maitreya continued; iti — thus; udāhṛtam — being spoken; ākarṇya — hearing; bhagavān nāradaḥ — the great personality Nārada; tadā — thereupon; prītaḥ — being pleased; pratyāha — replied; tam — him; bālam — the boy; sat-vākyam — good advice; anukampayā — being compassionate.
Translation: 
The sage Maitreya continued: The great personality Nārada Muni, upon hearing the words of Dhruva Mahārāja, became very compassionate toward him, and in order to show him his causeless mercy, he gave him the following expert advice.
Purport: 

Since the great sage Nārada is the foremost spiritual master, naturally his only activity is to bestow the greatest benefit upon whomever he meets. Dhruva Mahārāja, however, was a child, and so his demand was also that of a playful child. Still, the great sage became compassionate toward him, and for his welfare he spoke the following verses.