for every firstborn is mine. On the day I struck down every firstborn in the land of Egypt, I consecrated to myself every firstborn in Israel, both man and beast. They are mine; I am Yahweh.”
In context
11Yahweh spoke to Moses. He said, 12“Behold, I myself have taken the Levites from among the Israelites in place of every firstborn who opens the womb among the Israelites. The Levites shall be mine, 13for every firstborn is mine. On the day I struck down every firstborn in the land of Egypt, I consecrated to myself every firstborn in Israel, both man and beast. They are mine; I am Yahweh.” 14Yahweh spoke to Moses in the wilderness of Sinai. He said, 15“Number the sons of Levi by their ancestral houses, by their clans. You shall number every male one month old or older.”