John Gill

And the priest shall take the basket out of thine hand,.... To wave it, as Jarchi says, putting his hand under the hand of the owner, and so waving it; and this being waved to and fro towards the several corners of the earth, was an acknowledgment of the Lord being the proprietor of it: and set it down before the altar of the Lord thy God; that it might have some appearance of a sacrifice, and be a fit emblem of the spiritual sacrifice of praise, which is accepted upon the altar Christ, which sanctifies every gift.