זוהר שמות — דף קלג ע”א

The Kedushah of Yotzer Or is said seated because it sanctifies the Shekhinah of the lower world. The Kedushah of the Amida repetition is said standing to draw supernal holiness downward. A third Kedushah, an addition of holiness after the prayer, is said in Aramaic for each individual to draw additional holiness upon himself. The four furnishings (bed, table, chair, candelabra) correspond to the patriarchs and prepare the Shekhinah to appear before the supernal King.