Aaron is to present the Levites before the LORD as a wave offering from the sons of Israel, so that they may perform the service of the LORD.
KJV
And Aaron shall offer the Levites before the LORD [for] an offering of the children of Israel, that they may execute the service of the LORD.
ASV
and Aaron shall offer the Levites before Jehovah for a wave-offering, on the behalf of the children of Israel, that it may be theirs to do the service of Jehovah.