Unity retained by Bnei Yisrael

בפסוק זכור ימות עולם כו' בהנחל עליון גוים בהפרידו בני אדם כו'.

On the verse "Remember the days of old… when the Most High gave the nations their inheritance, when He separated the children of man…"

The Sefas Emes opens with this verse from Ha'azinu, which describes Hashem apportioning the nations and setting Bnei Yisrael apart.

כתבנו כבר במ"א הענין שנשאר האחדות אצל בנ"י.

We have already written elsewhere about the matter that the achdus (oneness) remains with Bnei Yisrael.

When the nations were divided up and assigned their portions, the quality of unity — connection to the one Source — was left specifically with Bnei Yisrael.

ודבר זה מתקיים בכל שנה כמו שהי' בתחילת הבריאה בכלל כן יש בכל שנה שיורד החיים בראש השנה משמים והיא בחי' השורש והאחדות כנ"ל.

And this matter is fulfilled every year: just as it was at the beginning of creation in general, so too each year the life-force descends from Heaven on Rosh Hashanah, and this is the aspect of the root and the unity, as above.

What happened once at creation recurs annually — on Rosh Hashanah a fresh life-force comes down from Heaven, and at that moment it is still in its undivided, unified state at the root.

ואח"כ נמנע מרשעים אורם וניתן לע' אומות לכל אחד חלק שלו כמ"ש שבעים פרים נגד ע' אומות.

And afterward their light is withheld from the resha'im, and it is given to the seventy nations, to each one its portion, as it is said: seventy bulls corresponding to the seventy nations.

After this unified descent, the light is parceled out to the seventy nations, each receiving its allotted share — represented by the seventy bulls offered over Sukkos.

ולבנ"י נשאר האחדות כמ"ש עצרת תהי' לכם.

And for Bnei Yisrael the unity remains, as it is written, "it shall be an atzeres for you."

While the nations get divided portions, Bnei Yisrael retain the undivided unity itself — expressed in Shemini Atzeres, "for you" alone.

כי להם יש אחיזה במעשה ולבנ"י בשורש הכל שהוא שמיני שלמעלה מז' ימי הבנין:

For they (the nations) have a grasp in the "deed," while Bnei Yisrael have a grasp in the root of everything, which is the "eighth" that is above the seven days of building.

The nations are bound to the finished, fragmented world of "action" (the seven days of creation), whereas Bnei Yisrael are rooted in the unified Source — the "eighth," which transcends the natural sevenfold order of creation.

Summary: When Hashem apportioned the nations at the dawn of history, the quality of unity and connection to the one Source remained with Bnei Yisrael. This recurs every year: on Rosh Hashanah a unified life-force descends from Heaven, and afterward it is divided among the seventy nations (the seventy bulls), each receiving its share of the "deed" — while Bnei Yisrael retain the undivided unity itself, rooted in the "eighth" of Shemini Atzeres that stands above the sevenfold order of creation.