זוהר שמות — דף עו ע”ב

Parasha Yitro, folio 76b — Israel left Egypt as servants and Moses called them sons through the holy spirit. Kabbalistic physiognomy reveals that hair length and color disclose the depths of the soul. The sign of the forehead indicates the inner capacity to contain knowledge and receive the holy spirit. These secrets allow one to know a person in their depth. Blessed are the companions who merited knowing these secrets and standing before the Holy One Blessed be He in the World to Come.