זוהר שמות — דף קסה ע”ב

The holy heaven upon which the Holy One, blessed be He, rides cannot bear sadness, which is why the High Priest entered it only with joy. When a person suffers, the Shekhinah shares his pain, as it is said: in all their affliction He was afflicted. The inner wisdom within a person is a supreme secret revealed only to deep thinkers, and one who meditates upon it perceives the supreme secrets of the world. The righteous who walk the proper path merit to serve within this holy heaven and to share in its joy.