Moshe's blessing as the Torah's flowing waters

איתא במד' וזאת הברכה דהג' אבות ומשה רע"ה ברכו את ישראל במקום שסיים זה פתח אחריו השני ע"ש.

It is brought in the Midrash on "And this is the blessing" (Devarim 33:1) that the three Avos and Moshe Rabbeinu blessed Yisrael — where one finished, the next began after him; see there.

The Midrash describes a continuous chain of blessing: Avraham, Yitzchak, and Yaakov each blessed Bnei Yisrael, and Moshe Rabbeinu picked up exactly where they left off, completing the sequence.

ונראה דהג' רגלים ברכת האבות ושמ"ע ברכת מרע"ה.

And it appears that the three festivals are the blessing of the Avos, and Shemini Atzeres is the blessing of Moshe Rabbeinu.

The Sefas Emes maps the chain onto the calendar: the three regalim (Pesach, Shavuos, Sukkos) embody the threefold blessing of the three Avos, while Shemini Atzeres — the added eighth day — is the concluding blessing of Moshe Rabbeinu.

לכן קורין בשמחת תורה וזאת הברכה.

Therefore we read "And this is the blessing" on Simchas Torah.

This is why the parsha of Moshe's blessing is read precisely on Simchas Torah (Shemini Atzeres) — that day is itself the embodiment of Moshe Rabbeinu's blessing.

וזו הברכה על כל ימי השנה.

And this blessing is for all the days of the year.

The blessing concentrated on this day flows outward to cover the entire coming year.

לכן נחלקת לי"ב שבטים לכל אחד ברכה בפ"ע לכל י"ב חדשי השנה.

Therefore it is divided among the twelve tribes, each one a blessing of its own, corresponding to the twelve months of the year.

Moshe's blessing is given tribe by tribe — twelve distinct blessings — which align with the twelve months, so that each month draws from its own portion of the annual blessing.

ומצינו ביעקב ומשה שניהם ברכו לי"ב שבטים.

And we find that both Yaakov and Moshe blessed the twelve tribes.

Both Yaakov (at the end of Bereishis) and Moshe (at the end of Devarim) gave parting blessings to all twelve tribes — and the next line explains what unites them.

כי שניהם בחי' התורה.

For both of them are the aspect of the Torah.

What Yaakov and Moshe share is that each represents the Torah itself — and the following lines bring the source for each.

יעקב כתיב בי' תתן אמת ליעקב ואין אמת אלא תורה.

Concerning Yaakov it is written, "Grant truth to Yaakov" (Michah 7:20), and "truth" is nothing other than the Torah.

Yaakov is identified with emes (truth), and since Chazal teach that "truth" means Torah, Yaakov embodies the Torah.

ומרע"ה שר התורה.

And Moshe Rabbeinu is the master of the Torah.

Moshe is the one through whom the Torah was given, the "sar haTorah," so he too is the very aspect of Torah.

והתורה מתפרשת לי"ג מדות שנדרשת בהם.

And the Torah branches out into the thirteen middos (hermeneutical principles) by which it is expounded.

The single, undivided Torah unfolds into the thirteen interpretive principles through which its meanings are derived — a spreading-out of the one source into many channels.

כי התורה עצמה מים שאין להם סוף והברכה הוא שנתפשט לנחלים ונתיבות בי"ג מדות:

For the Torah itself is water that has no end, and the blessing is that it spreads out into rivers and pathways through the thirteen middos.

The Torah at its source is like an infinite, boundless sea of water. The "blessing" is the act of drawing that limitless source into defined rivers and channels — the thirteen middos — so that it can flow down and be received. Just as the one Torah branches into twelve tribal blessings for twelve months, the boundless Torah becomes accessible through its many interpretive pathways.

Summary: The chain of blessing from the three Avos (the three regalim) culminates in Moshe Rabbeinu's blessing (Shemini Atzeres/Simchas Torah), which spreads over the whole year, dividing into twelve tribal blessings for the twelve months. Both Yaakov and Moshe, who blessed all twelve tribes, embody the Torah — the boundless "water" whose blessing lies precisely in its branching out into rivers and pathways, the thirteen middos through which it can flow down to us.