SB 10.79.9
atha tair abhyanujñatah
kausikim etya brahmanaih
snatva sarovaram agad
yatah sarayur asravat
Translation:
Then, given leave by the sages, the Lord went with a contingent of brahmanas to the Kausiki River, where He bathed. From there He went to the lake from which flows the river Sarayu.