Rashi on Leviticus 13:46/רש"י על ויקרא י״ג:מ״ו

1בדד ישב HE SHALL ABIDE SOLITARY — This means that people who are unclean from other causes than that of leprosy shall not abide with him (Pesachim 67a; cf. Sifra). Our Rabbis said: Why is he (the leper) treated differently from other unclean persons that he should abide solitary? They replied: Because he, by slanderous statements, (cf. Numbers 12:10) parted man and wife, or a man from his friend, he must be parted from everybody (Arakhin 16b).

2מחוץ למחנה WITHOUT THE CAMP — outside the three camps (see Rashi on Leviticus 4:12; cf. Sifra, Tazria Parashat Nega'im, Chapter 13 14 and Pesachim 67a).