Listen for free to MP3 audio of Chapter 8
of the Book of Numbers, KJV

¹⁶ For they are wholly given unto me from among the children of Israel; instead of such as open every womb, even instead of the firstborn of all the children of Israel, have I taken them unto me.
¹⁷ For all the firstborn of the children of Israel are mine, both man and beast: on the day that I smote every firstborn in the land of Egypt I sanctified them for myself.
¹⁸ And I have taken the Levites for all the firstborn of the children of Israel.