Sefer Etz Chaim and Tanya

Both texts address birur and klipat-nogah through the transformation of impure elements into good. Text 1 (Etz Chaim) emphasizes the descending structural hierarchy of souls (domem, tzomeach, chai, medaber) and their klipot as material vessels, focusing on sacrifice as a mechanism for extracting purity from external shells. Text 2 (Tanya) emphasizes the ascent of consciousness and intellectual delight ('oneg b'moach chochmah) that transforms the 'waters' (mayim) of animal soul into divine pleasure, highlighting the inversion of desire itself rather than sacrificial extraction. Text 1 focuses on descending hierarchical refinement through external ritual; Text 2 focuses on ascending spiritual transformation through contemplative elevation. Both discuss transforming the impure into good (birur of klipat-nogah), but differ in mechanism and direction.