When the teeth grew in again, Varuṇa came and said to Hariścandra, “Now you can perform the sacrifice.” But Hariścandra then said, “O King, when the sacrificial animal becomes a kṣatriya and is able to shield himself to fight with the enemy, then he will be purified.”
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
पुनर्जाता यजस्वेति स प्रत्याहाथ सोऽब्रवीत् । सान्नाहिको यदा राजन् राजन्योऽथ पशुः शुचिः
punarjātā yajasveti sa pratyāhātha so'bravīt | sānnāhiko yadā rājan rājanyo'tha paśuḥ śuciḥ
SB 9.7.14