Srimad-Bhagavatam: Canto 9 - Chapter 1 - Verse 10
Sanskrit:
जात: सुतो ह्यनेनाङ्ग मां यजस्वेति सोऽब्रवीत् ।यदा पशुर्निर्दश: स्यादथ मेध्यो भवेदिति ॥ १० ॥
ITRANS:
jātaḥ suto hy anenāṅgamāṁ yajasveti so ’bravītyadā paśur nirdaśaḥ syādatha medhyo bhaved iti
Translation:
Thereafter, when the child was born, Varuṇa approached Hariścandra and said, “Now you have a son. With this son you can offer me a sacrifice.” In answer to this, Hariścandra said, “After ten days have passed since an animal’s birth, the animal becomes fit to be sacrificed.”