LXX Num 3:13

ἐμοὶ γὰρ πᾶν πρωτότοκον· ἐν ᾗ ἡμέρᾳ ἐπάταξα πᾶν πρωτότοκον ἐν γῇ Αἰγύπτου ἡγίασα ἐμοὶ πᾶν πρωτότοκον ἐν Ἰσραήλ· ἀπὸ ἀνθρώπου ἕως κτήνους ἐμοὶ ἔσονται· ἐγὼ Κύριος.

for all the firstborn are Mine. On the day I struck down every firstborn in the land of Egypt, I consecrated to Myself all the firstborn in Israel, both man and beast. They are Mine; I am the LORD.”