And the Lord spake unto Moses. This is another kind of tithe, i.e., a hundredth part of the whole produce, which the Levites paid to the priests. Some reckon a third kind; but I have given my reasons why I do not agree with this opinion. Assuredly it is not probable that in the same year double tithes were exacted and paid. Let this twofold division, therefore, be enough for us. A larger portion was given to the priests, not only as an honorable distinction, but. because greater holiness and integrity in expending them was expected from them; and also that they might meet many peculiar burdens. Lest then the Levites should be too sordid and niggardly, God declares that their theft would be no less wicked if they dealt dishonestly towards the priests, than as if the people should withhold any part of their own just share; for this is the object of the words, that the tithe of the tithes, which they are commanded to pay, should be as if they paid it from the threshing-floor and the wine-press, (ver. 27;) as though it were said that they were no more exempted from the second tithes, than the people from the first. The precept is then still further extended, viz., that they should offer a part of all the offerings. Thirdly, sincere liberality is inculcated upon them, that they should not lay aside as the priests' portion anything that was lean or out of condition, or in any respect of inferior quality, but that they should rather offer whatever was most choice; for this is what is meant by the word chlv, cheleb, [1] which some translate adeps; the word pinguedo seemed more suitable, in which, however, there is a metaphor contained.

Footnotes

1 - Ver. 30. A.V. "the best thereof." Margin, "Heb., fat." According to Facciolati, adeps, means liquid fat which does not readily become hard; and pinguedo, simply fat, "an oily substance in animals and other things."

And the Lord spake unto Moses,.... And not unto Aaron, because a tithe out of the tithe was to be given to Aaron, as Aben Ezra observes, and it was not so proper that he should have this order to deliver to the Levites, in which he and his sons were so much concerned, and therefore it was given to Moses to acquaint them of it:
saying; as follows.

Appropriation of the Tithe. - Numbers 18:26. When the Levites took (received) from the people the tithe assigned them by Jehovah, they were to lift off from it a heave-offering for Jehovah, a tithe of the tithe for Aaron the priest (i.e., for the priesthood; see at Numbers 18:20). "Your heave-offering shall be reckoned to you as the corn of the threshing-floor, and the fulness (see Exodus 22:28) of the wine-press," i.e., according to Numbers 18:30, as the revenue of the threshing-floor and wine-press; that is to say, as corn and wine which they had reaped themselves.