SB 8.6.17

eka eveśvaras tasmin
 sura-kārye sureśvaraḥ
vihartu-kāmas tān āha
 samudronmathanādibhiḥ
Synonyms: 
ekaḥ — alone; eva — indeed; īśvaraḥ — the Supreme Personality of Godhead; tasmin — in that; sura-kārye — the activities of the demigods; sura-īśvaraḥ — the Lord of the demigods, the Supreme Personality of Godhead; vihartu — to enjoy pastimes; kāmaḥ — desiring; tān — unto the demigods; āha — said; samudra-unmathana-ādibhiḥ — by activities of churning the ocean.
Translation: 
Although the Supreme Personality of Godhead, the master of the demigods, was capable of performing the activities of the demigods by Himself, He wanted to enjoy pastimes in churning the ocean. Therefore He spoke as follows.