| Clarke's Commentary on the Bible Thus ye also shall offer a heave-offering - As the Levites had the tithe of the whole land, they themselves were obliged to give the tithe of this tithe to the priests, so that this considerably lessened their revenue. And this tithe or tenth they were obliged to select from the best part of the substance they had received, Numbers 18:29, etc. A portion of all must be given to God, as an evidence of his goodness, and their dependence on him. See the end at Numbers 20:28.
Gill's Exposition of the Entire BibleThus you also shall offer an heave offering unto the Lord,.... As the Israelites did when they paid tithes to them, Numbers 18:24, of all your tithes which ye receive of the children of Israel; which heave offering was a tenth part of them: and ye shall give thereof the Lord's heave offering to Aaron the priest; that is, the said tenth part of the tithe was to be given not to Aaron only, as the high priest, as some have thought, and so to his successors in the high priesthood; but to him and his sons, even to all the priests in common, the high priest having his share of it; and Josephus (o) is clear for it, that the tithe of the annual fruits was paid to the Levites, and to the priests. Hecataeus, an Heathen writer, who lived in the times of Alexander the great, says (p), that all the priests of the Jews received the tenth of whatsoever was produced, and ministered things in common, and were 1500 in number. (o) Antiqu. l. 4. c. 4. sect. 3.((p) Apud Joseph. contr. Apion. l. 1. sect. 22.
Geneva Study BibleThus ye also shall offer an heave offering unto the LORD of all your tithes, which ye receive of the children of Israel; and ye shall give thereof the LORD's heave offering to Aaron the priest.
Wesley's Notes 18:28 To Aaron - And to his children, who were all to have their share herein.
Matthew Henry's Concise Commentary18:20-32 As Israel was a people not to be numbered among the nations, so Levi was a tribe to be distinguished from the rest. Those who have God for their Inheritance and their Portion for ever, ought to look with holy contempt and indifference upon the possessions of this world. The Levites were to give God his dues out of their tithes, as well as the Israelites out of their increase. See, in ver. 31, the way to have comfort in all our worldly possessions, so as to bear no sin by reason of them. 1. We must be sure that what we have is got honestly and in the service of God. That meat is best eaten which is first earned; but if any will not work, neither shall he eat, 2Th 3:10. 2. We must be sure that God has his dues out of it. We have the comfort of our substance, when we have honoured the Lord with it. Ye shall bear no sin by reason of it, when ye have heaved the best from it. We should give alms of such things as we have, that all may be holy and comfortable to us. | 
