Sefer Etz Chaim and Tanya

Both texts engage with birur (clarification/elevation) of holy sparks from admixture with impurity, specifically referencing klipat-nogah. Etz Chaim 5:2 focuses on birur occurring through Torah study, emphasizing the separation of 'good mixed with bad' specifically within 'vessels of nogah' (כלי של נוגה) and not within other klipot. The Tanya passage emphasizes birur through contemplative practice and transforming base desires (תאוות) into vessels for divine love, describing the elevation of 'waters' from the animal soul into holiness. Etz Chaim stresses structural separation (the bad resides only in nogah's vessels), while Tanya stresses transformative elevation (removing 'soiled garments' to reveal underlying potential). Both accept that klipat-nogah contains mixed good-bad elements amenable to elevation, but Etz Chaim frames this as separation within particular vessels, while Tanya frames it as transforming existing animal desires into spiritual ones.