Nefesh HaChayim and Tanya

Both texts discuss chalal (empty space) and kav (line) within tzimtzum framework. Nefesh HaChayim emphasizes chalal as a pedagogical mechanism—necessary concealment enabling progressive revelation through chains (shlashlus) even to impure forces, with kav as an extremely thin trace (reshmah daka) that doesn't reach the lowest realms. Tanya emphasizes kav as the essential garment (malbush) of divine contraction itself, with souls existing as tzimtzum godliness rather than separate entities. Nefesh HaChayim focuses on chalal's function in cosmic hierarchy; Tanya focuses on kav's role in constituting soul ontology. Both affirm both concepts but stress different aspects of their metaphysical role.