Yaakov Avinu arrived in Beis El when the sun set unexpectedly, and so he slept the night there. When he woke up, he declared his shock that he had slept in such a holy spot, the site of the future Beis HaMikdash.
In our Sicha the Rebbe asks about Yaakov’s laying down to sleep “‘in that place’ — the place of the Mikdash (מקום המקדש)…”
This expression “מקום המקדש” should grab our attention, for it is the expression the Rebbe uses in Kuntres Beis Rabbeinu Sh’b’Bavel, which was published and distributed several weeks prior to this Sicha. In that Kuntres the Rebbe states that 770 is the מקום המקדש. Are we “sleeping” in the מקום המקדש and don’t realize it?
However, the Rebbe says that it can be interpreted in a positive fashion: at the time that one lies down to sleep there is equality between the head and the feet. Although this is a tremendous descent from the perspective of the revelations of the power of the respective parts of the body (גלוים), at the same time it reflects on the revelation of Atzmus — the Essence and Being of Divinity — which transcends all differences such as head and foot, higher and lower, spiritual and physical. The complete unification of lower and higher.
After this, even when Yaakov “awakens from his slumber” (a hint to the Rebbe’s expressions in the Dvar Malchus sicha of Toldos), and the head then returns to its lofty level compared to the foot, nonetheless the “equality” generated by the revelation of Atzmus — the Essence — remains, a dwelling place down below: a “dira b’tachtonim“
So, our sleeping on the site of the greatest Divine revelations, מקום המקדש, is connected with the revelation of the Divine Essence and Being itself. And the call to “open our eyes” (via learning Chassidus and the subjects of Geulah and Moshiach) is to draw down the revelation of the Essence into the physical world, which is ready to be a vessel for these revelations!