Numbers 8:14-16

Young's Literal Translation

¹⁴ and thou hast separated the Levites from the midst of the sons of Israel, and the Levites have become Mine;

¹⁵ and afterwards do the Levites come in to serve the tent of meeting, and thou hast cleansed them, and hast waved them -- a wave-offering.

¹⁶ `For they are certainly given to Me out of the midst of the sons of Israel, instead of him who openeth any womb -- the first-born of all -- from the sons of Israel I have taken them to Myself;