SB 9.7.11

nirdaśe ca sa āgatya
 yajasvety āha so ’bravīt
dantāḥ paśor yaj jāyerann
 atha medhyo bhaved iti
Word for word: 
nirdaśe — after ten days; ca — also; saḥ — he, Varuṇa; āgatya — coming there; yajasva — now sacrifice; iti — thus; āha — said; saḥ — he, Hariścandra; abravīt — replied; dantāḥ — the teeth; paśoḥ — of the animal; yat — when; jāyeran — have appeared; atha — then; medhyaḥ — fit for being sacrificed; bhavet — will become; iti — thus.
Translation: 
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.”