John Calvin Reformed @genevareformer

25. 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.

Matthew Henry Presbyterian @wholebiblehenry

Here is a further account of the provision that was made both for the Levites and for the priests, out of the country. I. They must have no inheritance in the land; only cities to dwell in were afterwards allowed them, but no ground to occupy: Thou shalt not have any part among them, Num 18:20.

Commenting on Numbers 18:20-32

John Gill Reformed Baptist @doctorgill

Thus speak unto the Levites, and say unto them,.... Aaron was to tell them what a provision would be made for them on account of their service, but Moses was to inform them what part Aaron was to have out of it: when ye take of the children of Israel the tithes which I have given you from them for your inheritance; which was done...