Albert Barnes Commentary Ezekiel 48:18-19

"And the residue in the length, answerable unto the holy oblation, shall be ten thousand eastward, and ten thousand westward; and it shall be answerable unto the holy oblation; and the increase thereof shall be for food unto them that labor in the city. And they that labor in the city, out of all the tribes of Israel, shall till it." — Ezekiel 48:18-19 (ASV)

Then, that serve - that is, the cultivators or farmers.

Formerly, the city belonged to Benjamin and Judah, and its inhabitants were mainly from these tribes. Now all the tribes are to have equal part in it, and avoid jealousies (compare 2 Samuel 19:43).