Srimad Bhagavatam Canto 10, Chapter 26, Text 14

 SB 10.26.14

kva sapta-hayano balah
 kva mahadri-vidharanam
tato no jayate sanka
 vraja-natha tavatmaje
 
Translation: 
 
On the one hand this boy is only seven years old, and on the other we see that He has lifted the great hill Govardhana. Therefore, O King of Vraja, a doubt about your son arises within us.
Srimad Bhagavatam Canto 10, Chapter 26, Text 13
Srimad Bhagavatam Canto 10, Chapter 26, Text 15