Jewish mourning custom draws on the layered soul the Kabbalistic sources describe, and Neshamah, the higher, intellective soul, is held in some sources to ascend more slowly and to a further destination than Nefesh or Ruach, its return described as a return to the divine source of understanding itself rather than a settling near the body or a resolution of emotional conduct. Because Neshamah is tied in the tradition to Torah study and higher understanding during life, mourning customs in some communities place particular weight on continued study undertaken in a deceased relative's name as an act that specifically benefits this level of the soul.
The custom of reciting the Kaddish, a prayer that does not mention death but praises the divine, is explained by some later authorities as directed toward elevating exactly this higher aspect of the soul, distinct from the more bodily focused practices associated with Nefesh.
This mourning centred use sits alongside Neshamah's more abstract place in Kabbalistic cosmology, where it corresponds to the third of the Four Worlds; the funerary application treats the doctrine as guidance for the living's ongoing obligations to the dead rather than only a map of the soul's structure.