Negative commandment · Lo Ta’aseh #170 of 613
That the tribe of Levi not take a portion in the spoils
שלא ייקח כל שבט לוי חלק בביזה בשעת כיבוש הארץ
The verse · Devarim 18:1
לֹא־יִהְיֶה לַכֹּהֲנִים הַלְוִיִּם כׇּל־שֵׁבֶט לֵוִי חֵלֶק וְנַחֲלָה עִם־יִשְׂרָאֵל אִשֵּׁי ה׳ וְנַחֲלָתוֹ יֹאכֵלוּן
“The priests the Levites, all the tribe of Levi, shall have no part or inheritance with Yisra᾽el: the offerings of the Lord made by fire, and his dues shall they eat.”
The Rambam’s words
For the tribe of Levi not to take a portion of the spoils in the conquest of Eretz Yisrael, as [Deuteronomy 18:1] states: "The priests and the Levites shall not receive a portion or an inheritance."
שלא ייקח כל שבט לוי חלק בביזה בשעת כיבוש הארץ, שנאמר "לא יהיה לכוהנים הלויים . . . חלק ונחלה" (דברים יח,א).
Why · Sefer HaChinuch #505
That the tribe of Levi not take a portion in the spoils
“It is from the roots of the commandment [that] since they are the servants of G-d, it is not fit for them to use vessels snatched from the hand of people in war with the sword, the spear and the javelin.”
Who & when
“And this commandment is practiced at the time of the [Temple] with the tribe of the Levites.”
Where in the Mishneh Torah
Hilchot Sabbatical Year and the Jubilee הלכות שמיטה ויובל