After ten days, Varuṇa came again and said to Hariścandra, “Now you can perform the sacrifice.” Hariścandra replied, “When an animal grows teeth, then it becomes pure enough to be sacrificed.”
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
निर्दशे च स आगत्य यजस्वेत्याह सोऽब्रवीत् । दन्ताः पशोर्यज्जायेरन्नथ मेध्यो भवेदिति
nirdaśe ca sa āgatya yajasvetyāha so'bravīt | dantāḥ paśoryajjāyerannatha medhyo bhavediti
SB 9.7.11