On God/Shekinah in Targumim, 2nd Temple Period, and rabbinic sources, see this exhaustive entry by Kaufman Kohler and Ludwig Blau in the 1906 Jewish Encyclopedia available online here. “The term,” they explain, “was used by the Rabbis in place of ‘God’ where the anthropomorphic expressions of the Bible were no longer regarded as proper.” Shekkinah relates to God’s descending, dwelling, resting “presence.” I would note that, in the sources, the Shekhina is more like a shell than an essence. It dwells not “in” the human person, but rests “upon” and settles around the person.
