One verse

Srimad Bhagavatam 7.1.36

7.1.36

श्रीनारद उवाच एकदा ब्रह्मण: पुत्रा विष्णुलोकं यद‍ृच्छया । सनन्दनादयो जग्मुश्चरन्तो भुवनत्रयम् ॥ ३६ ॥

sri-narada uvaca ekada brahmanah putra visnu-lokam yadrcchaya sanandanadayo jagmus caranto bhuvana-trayam

sri-naradah uvaca
Sri Narada Muni said
ekada
once upon a time
brahmanah
of Lord Brahma
putrah
the sons
visnu
of Lord Visnu
lokam
the plane
yadrcchaya
by chance
sanandana-adayah
Sanandana and the others
jagmuh
went
carantah
traveling about
bhuvana-trayam
the three worlds.

The great saint Narada said: Once upon a time when the four sons of Lord Brahma named Sanaka, Sanandana, Sanatana and Sanat-kumara were wandering throughout the three worlds, they came by chance to Visnuloka.