Srimad-Bhagavatam: Canto 9 - Chapter 1 - Verse 30
Sanskrit:
व्रतान्ते कार्तिके मासि त्रिरात्रं समुपोषित: ।स्नात: कदाचित् कालिन्द्यां हरिं मधुवनेऽर्चयत् ॥ ३० ॥
ITRANS:
vratānte kārtike māsitri-rātraṁ samupoṣitaḥsnātaḥ kadācit kālindyāṁhariṁ madhuvane ’rcayat
Translation:
In the month of Kārtika, after observing that vow for one year, after observing a fast for three nights and after bathing in the Yamunā, Mahārāja Ambarīṣa worshiped the Supreme Personality of Godhead, Hari, in Madhuvana.