Srimad Bhagavatam Canto 10, Chapter 27, Text 14

 SB 10.27.14

sri-suka uvaca
evam sankirtitah krsno
 maghona bhagavan amum
megha-gambhiraya vaca
 prahasann idam abravit
 
Translation: 
 
Sukadeva Gosvami said: Thus glorified by Indra, Lord Krsna, the Supreme Personality of Godhead, smiled and then spoke to him as follows in a voice resonant like the clouds.
 
Purport: 
 
Although in this pastime Lord Krsna appeared to be a small boy, the words megha-gambhiraya vaca indicate that He spoke to Indra with the deep, resonant voice of the Supreme Lord.
Srimad Bhagavatam Canto 10, Chapter 27, Text 13
Srimad Bhagavatam Canto 10, Chapter 27, Text 15