Numbers 18:11
And this is thine; the heave offering of their gift, with all the wave offerings of the children of Israel: I have given them unto thee, and to thy sons and to thy daughters with thee, by a statute for ever: every one that is clean in thy house shall eat of it.
Israel's sacred gifts and offerings were set apart for the use of the priests. The heave offerings and wave offerings of the children of Israel belonged to them by divine appointment. The first-fruits were to be brought before the Lord at the sanctuary. Once presented there, they were then devoted to the priests for their support.