SB 10.28.1

śrī-bādarāyaṇir uvāca
ekādaśyāṁ nirāhāraḥ
 samabhyarcya janārdanam
snātuṁ nandas tu kālindyāṁ
 dvādaśyāṁ jalam āviśat
Synonyms: 
śrī-bādarāyaṇiḥ uvāca — Śrī Bādarāyaṇi (Śukadeva Gosvāmī) said; ekādaśyām — on Ekādaśī (the eleventh day of the lunar month); nirāhāraḥ — fasting; samabhyarcya — having worshiped; janārdanam — Lord Janārdana, the Supreme Personality of Godhead; snātum — in order to bathe (before breaking the fast at its prescribed completion); nandaḥ — Nanda Mahārāja; tu — but; kālindyām — in the river Yamunā; dvādaśyām — on the twelfth day; jalam — the water; āviśat — entered.
Translation: 
Śrī Bādarāyaṇi said: Having worshiped Lord Janārdana and fasted on the Ekādaśī day, Nanda Mahārāja entered the water of the Kālindī on the Dvādaśī to take his bath.