Rashi on Numbers 31:24/רש"י על במדבר ל״א:כ״ד

1אל המחנה [YE SHALL BE CLEAN, AND AFTERWARDS] YE MAY COME INTO THE CAMP — into the camp where is the Divine Presence (מחנה שכינה), because a person unclean by reason of a corpse does not require expulsion from the camp of the Levites and the camp of the Israelites, (but only from the camp of the Shechina, and consequently the permission to come into the camp after purification must mean into the מחנה שכינה; Pesachim 67a; cf. Rashi on 5:2).