For if His light had not spread over all created beings by its enclothing, as it were, in these holy sefirot, how could the created beings merit recognizing Him and how could the verse be fulfilled: “The whole earth is full of His glory”?60Isaiah 6:3. The author of the Sulam explains: The meaning is that the Zohar is thereby explaining the Divine desire to appear to the souls as though these changes in the sefirot are in Him. This is in order to give the souls the possibility of sufficient recognition and perception of Him, since then the verse “the whole earth is full of His glory” will be fulfilled, as we stated in section #33# above.
Perceiving Ein Sof Through Sefirot Like Stained Glass
Baal HaSulam's Preface to Zohar 41:1