Having explained that Beriah is the abode of souls that served G‑d with intellectual love and fear, and Yetzirah — of souls that served Him with natural love and fear, the Alter Rebbe will now discuss the divine service of those souls whose abode is the World of Atzilut. The quality of their divine service, he explains, surpasses even that of intellectual love and fear. This is the level of those tzaddikim who become veritable "chariots" for G‑d: they have no will save His Will, and their every act testifies to their utter self-nullification before Him.
ועולם האצילות, שהוא למעלה מהשכל וההשגה וההבנה לשכל נברא
The World of Atzilut is beyond the intelligence, grasp and understanding of a created being's intellect. Even a spiritual being in the World of Beriah is after all a created being, and Atzilut is beyond its grasp as well.
כי חכמתו ובינתו ודעתו של אין סוף ברוך הוא מיוחדות שם בו בתכלית היחוד
For the Chochmah, Binah and Daat of the Ein Sof are united with Him there (in Atzilut) in perfect unity,
ביחוד עצום ונפלא, ביתר שאת ויתר עז לאין ק׳ מבעולם הבריאה
in a profound and wonderful unity infinitely superior to that [unity] found in Beriah.
כי שם ירדו להאיר בבחינת צמצום
For there they descended to illuminate [only] to a restricted ("contracted") degree. The ChaBaD of Atzilut (referred to here as "ChaBaD of Ein Sof") radiate in Beriah only after their light is "contracted",
כדי שיוכלו שכלים נבראים לקבל מהן חב״ד, לידע את ה׳ ולהבין ולהשיג איזו השגה באור אין סוף ברוך הוא
so as to enable the intellect of created beings (namely, the angels and souls of Beriah) to receive ChaBaD — wisdom, understanding and knowledge — from [these Sefirot of Atzilut], so that they might know G‑d, and so that they might grasp and comprehend something of the Ein Sof-light,
כפי כח שכלים הנבראים, שהם בעלי גבול ותכלית
to the extent that the intellect of finite, limited, created beings is capable of understanding.
שלא יתבטלו במציאותם ולא יהיו בגדר נבראים כלל, רק יחזרו למקורם ושרשם, שהוא בחינת אלקות ממש
To achieve this purpose a "contraction" of ChaBaD of Atzilut was necessary, lest they (the created beings of Beriah) dissolve out of existence and lest they furthermore cease altogether to exist as created beings, reverting instead to their source and root, namely G‑dliness itself.
Were the ChaBaD of Atzilut to shine forth in Beriah without being "contracted", allowing the creatures of Beriah to grasp G‑dliness as it radiates in the Sefirot of Atzilut, these creatures would be overwhelmed by the G‑dly illumination beyond their capacity to absorb, and would dissolve out of existence.
Hence, the Alter Rebbe will now continue, it is only the G‑dliness in a "contracted" ChaBaD that creatures of Beriah can grasp and absorb (and even then, only to the extent of their limited capacity); the light of ChaBaD in its pristine state, as in Atzilut, is beyond them.
