Srimad-Bhagavatam: Canto 4 - Chapter 1 - Verse 24
Sanskrit:
एषोऽश्वमेधाञ् शतमाजहारसरस्वती प्रादुरभावि यत्र । अहार्षीद्यस्य हयं पुरन्दर:शतक्रतुश्चरमे वर्तमाने ॥ २४ ॥
ITRANS:
eṣo ’śvamedhāñ śatam ājahārasarasvatī prādurabhāvi yatraahārṣīd yasya hayaṁ purandaraḥśata-kratuś carame vartamāne
Translation:
At the source of the river Sarasvatī, this King will perform one hundred sacrifices known as aśvamedha. In the course of the last sacrifice, the heavenly King Indra will steal the sacrificial horse.