זוהר שמות — דף צד ע”ב

An elder questions Rabbi Shimon about the additional Shabbat soul and the commandment to do no work. Rabbi Shimon responds that the soul of the righteous ascends and joins the Shekhinah on Shabbat. The laws of the Hebrew slave symbolize the soul descending to this world for a limited term of service. All the ordinances of parashat Mishpatim relate to the order of souls in the upper and lower worlds.