Numbers 8:11

And Aaron shall offer the Levites before the Lord, in a gesture of waving, whereby they were transferred from the position of ordinary members of the congregation to that of God's servants in a peculiar sense, for an offering of the children of Israel, for that is the meaning the ceremony intended to convey to the onlooker, that they may execute the service of the Lord, become a part of that army of Jehovah, of Hia true soldiers, that waged a spiritual warfare in His interest. "Most likely Aaron pointed to the Levites, and then waved his hands as in ordinary cases of making the offering. "