The unbroken chain of tikkun in Klal Yisrael

במדרש וזאת הברכה העובר לפני התיבה שטעה כיצד יעשהו יעבור אחר תחתיו כו' משה רע"ה פתח בזאת שסיים בו יעקב כו' ע"ש.

In the Midrash on "V'Zos HaBerachah": one who passes before the amud (leads the davening) and errs — what should be done? Another passes in his place, [continuing from where he left off]... Moshe Rabbeinu opened with "Zos" with which Yaakov had concluded, see there.

The Midrash compares Moshe to a replacement chazzan who picks up exactly where the previous one stopped: Moshe began his blessing with the very word "Zos" with which Yaakov had ended his blessings to the shevatim.

ביאור הענין כי זה ענין השלימות שבישראל שהם כלי המחזיק ברכה כמ"ש אין כלי מחזיק ברכה אלא שלום כו'.

The explanation of the matter: this is the matter of the completeness within Yisrael, that they are the vessel which holds blessing, as it is said, "There is no vessel that holds blessing other than shalom (peace)" (Uktzin 3:12).

Klal Yisrael's wholeness is what makes them a vessel able to contain berachah — and the only such vessel is shalom, the unbroken unity of the people.

שאף שיש חטאים בישראל הם במקרה.

That even though there are sinners in Yisrael, they are [so] only incidentally.

Sin is never the essence of Yisrael; it is accidental, a passing blemish, not the true nature of the people.

אבל בכלל ישראל לעולם יש אחד שיכול להחזיר ולתקן.

But within Klal Yisrael there is always someone who can restore and repair.

The collective is never without a tzaddik or capable individual who can effect tikkun and bring the others back — the chain of repair is never broken.

וזה ענין משנה תורה וזאת הברכה שמרע"ה חזר והתקין כל מה שעבר עליהם מהתחלת יצ"מ עד זמן פטירתו.

And this is the matter of Mishneh Torah (Devarim) and V'Zos HaBerachah, that Moshe Rabbeinu went back and repaired all that had befallen them from the beginning of Yetzias Mitzrayim until the time of his passing.

In the final book and final parshah, Moshe acts as the great mesakein, gathering up and mending everything that had gone amiss across the entire forty years.

וז"ש המד' כי לא פסק התקון ובא אחר ומתחיל במקום שסיים הראשון כנ"ל:

And this is what the Midrash means: that the tikkun never ceases, and another comes and begins from the place where the first one left off, as above.

The work of repair is continuous across the generations — like a relay of leaders, each one takes up the tikkun exactly where his predecessor concluded, so the blessing is never lost.

Summary: Just as a replacement chazzan continues from where the first left off, Moshe opened V'Zos HaBerachah with the very word with which Yaakov had ended his blessings — for Klal Yisrael's wholeness (shalom) makes them a vessel that holds blessing. Sin in Yisrael is only incidental, and there is always someone able to restore and repair; thus the work of tikkun never ceases but passes unbroken from one leader to the next.