Srimad Bhagavatam Canto 10, Chapter 46, Text 29

SB 10.46.29

tayor ittham bhagavati
 krsne nanda-yasodayoh
viksyanuragam paramam
 nandam ahoddhavo muda
 
Translation: 
 
Uddhava then joyfully addressed Nanda Maharaja, having clearly seen the supreme loving attraction he and Yasoda felt for Krsna, the Supreme Personality of Godhead.
 
Purport: 
 
If Uddhava had seen Nanda and Yasoda actually suffering, he would not have reacted with joy. But in fact all emotions on the spiritual platform are transcendental bliss. The so-called anguish of the pure devotees is another form of loving ecstasy. This was clearly seen by Uddhava, and thus he spoke as follows.
Srimad Bhagavatam Canto 10, Chapter 46, Text 28
Srimad Bhagavatam Canto 10, Chapter 46, Text 30