TSK
Treasury of Scripture Knowledge references in WEB.
For they are wholly given to me from among the children of Israel; instead of all who open the womb, even the firstborn of all the children of Israel, I have taken them to me.
I have given the Levites as a gift to Aaron and to his sons from among the children of Israel, to do the service of the children of Israel in the Tent of Meeting, and to make atonement for the children of Israel; that there be no plague among the children of Israel, when the children of Israel come near to the sanctuary."
I, behold, I have taken your brothers the Levites from among the children of Israel: to you they are a gift, given to Yahweh, to do the service of the Tent of Meeting.
Then David said, "No one ought to carry the ark of God but the Levites. For Yahweh has chosen them to carry the ark of God, and to minister to him forever."
They set the priests in their divisions, and the Levites in their courses, for the service of God, which is at Jerusalem; as it is written in the book of Moses.
Therefore he says, "When he ascended on high, he led captivity captive, and gave gifts to men."