Likutei Sichos, vol 27 Metzora 2, Rabbi Chaim Wolosow
https://www.torahrecordings.com/likutei-sichos/027/008_002 The Rebbe explains why the Torah separates a metzora’s impurity and purification, contrasting it with plagues of homes. Revealing the paradox of nega, he shows how the lowest descent leads to the highest ascent—transforming nega into oneg through teshuvah and the essence of the soul.