Srimad Bhagavatam Canto 10, Chapter 49, Text 27

SB 10.49.27

tathapi sunrta saumya
 hrdi na sthiyate cale
putranuraga-visame
 vidyut saudamani yatha
 
Translation: 
 
Even so, gentle Akrura, because my unsteady heart is prejudiced by affection for my sons, these pleasing words of yours cannot remain fixed there, just as lightning cannot remain fixed in a cloud.
Srimad Bhagavatam Canto 10, Chapter 49, Text 26
Srimad Bhagavatam Canto 10, Chapter 49, Text 28