As an heave-offering unto the Lord, i.e. as a rent charge or an acknowledgment that they have and hold all their lands, and the fruits of it, from God's bounty. Note that the word heave-offering, which is for the most part understood of a particular kind of offerings heaved or lifted up to the Lord, is here used for any offering in general, as before, Numbers 18:8.
Related Commentaries of Numbers 18:24
Numbers 18:24
24 But the tithes of the children of Israel, which they offer as an heave offering unto the LORD, I have given to the Levites to inherit: therefore I have said unto them, Among the children of Israel they shall have no inheritance.