SB 10.51.42
so ’ham tavanugrahartham
guham etam upagatah
prarthitah pracuram purvam
tvayaham bhakta-vatsalah
Translation:
Since in the past you repeatedly prayed to Me, I have personally come to this cave to show you mercy, for I am affectionately inclined to My devotees.
Purport:
It is apparent from this verse that Mucukunda was a devotee of the Supreme Lord. He had prayed for the Lord’s association, and now Sri Krsna granted his fervent request.