TSK
Treasury of Scripture Knowledge references in KJV.
And thou shalt take the Levites for me (I [am] the LORD) instead of all the firstborn among the children of Israel; and the cattle of the Levites instead of all the firstlings among the cattle of the children of Israel.
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.
And I, behold, I have taken your brethren the Levites from among the children of Israel: to you [they are] given [as] a gift for the LORD, to do the service of the tabernacle of the congregation.