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.”
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
जातःसुतो ह्यनेनाङ्ग मां यजस्वेति सोऽब्रवीत् । यदा पशुर्निर्दशः स्यादथ मेध्यो भवेदिति
jātaḥsuto hyanenāṅga māṃ yajasveti so'bravīt | yadā paśurnirdaśaḥ syādatha medhyo bhavediti
SB 9.7.10