Comentario sobre Números 18:20

וחלק לא יהיה לך בתוכם [THOU SHALT NOT INHERIT THEIR LAND,] NEITHER SHALT THOU HAVE ANY PORTION IN THE MIDST OF THEM even in the spoil (Sifrei Bamidbar 119:1).

THOU [Aaron] SHALT HAVE NO INHERITANCE IN THEIR LAND. This means that you [Aaron] will not inherit a share amongst any one of all the tribes of Israel.²⁰⁹Thus they were excluded not only from having a central tribal land of their own but even from having smaller pieces of land throughout the other tribes. Neither shalt thou have [even] a small portion in their land at all, for the cities which were given to them [the Levites] were [also] cities of refuge, and were used by the rest of Israel. Now this admonition applies to the priests, and afterwards He mentioned with respect to the Levites: among the children of Israel they shall have no inheritance,²¹⁰Verse 23. just as He had admonished the priests. And our Rabbis interpreted the verse:²¹¹Sifre Korach 118. “Thou shalt have no inheritance in their land, as referring to the time when the Land was divided up [amongst the tribes]. Neither shalt thou have any portion among them, that is, a portion of the spoil [taken from a defeated enemy]. I am thy portion — you eat at My table.”²¹²In other words, while all Israel lives upon the yield of the land, the priests acquire their gifts directly from “the Table” of the Most High. See also “The Commandments,” Vol. II, pp. 163-166.
Chukath

בארצם לא תנחל, "you will not have an in heritance in their land, etc." According to Sifri this verse forbids the priests not only a share in the land but also a share in the spoils of war. This is based on the respective meaning of נחלה and חלק both of which appear twice in our verse. The Torah tells us that though the other tribes might be willing to share the loot with the priests and they might interpret the verse as only excusing them from sharing but not forbidding same, this is not so. The legislation is not comparable to the Shemittah legislation where we are told in Shevi-it 10,9 that the rabbis were delighted if a debtor volunteered to repay a debt which the creditor could no longer insist on collecting legally. To make the point quite clear the Torah wrote לא תנחל, you must not inherit. Had the Torah written nothing else I would have thought that only inheritance of land is actually forbidden but that accepting a share of the spoils of war is permissible. This is why the Torah had to add the word וחלק, "as well as any part." The reason the Torah added the word בתוכם may be understood when we look at Proverbs 1,14: גורלך תפיל בתוכנו, i.e. "accept part of our lot together with us." The prohibition applies only when the priests receive their share as part and parcel of the division between the tribes. If anyone wishes to give them some of the spoils in the form of a gift this is permissible.