Moshe embodies Torah's four levels

וזאת הברכה כו' הוא עצמו התורה כמ"ש במד' דתורה נקראת זאת כמ"ש וזאת התורה כו' שם משה.

"And this is the blessing" — this itself is the Torah, as the Midrash says that the Torah is called "this," as it is written, "And this is the Torah," and there it mentions Moshe.

The blessing with which Moshe Rabbeinu blessed Bnei Yisrael is none other than the Torah itself; the word "this" (zos) is a name Chazal give to the Torah.

והענין הוא כי התורה יש בה כמה דרכים כדלעיל.

The matter is that the Torah contains many paths, as above.

The Torah is not one flat surface; it holds many layers and ways of being grasped.

ומרע"ה הוא עצם התורה והנחיל כחו לבנ"י כמ"ש תורה צוה לנו משה מורשה כו'.

And Moshe Rabbeinu is the very essence of the Torah, and he bequeathed his power to Bnei Yisrael, as it is written, "The Torah that Moshe commanded us is an inheritance (morashah)."

Moshe was the embodiment of Torah, and he passed that very capacity down as an everlasting inheritance to every Jew.

ותורתו של מדריגת מרע"ה נקראת זאת התורה.

And the Torah of the level of Moshe Rabbeinu is called "this is the Torah."

The clear, fully revealed dimension of Torah belongs to Moshe's madreigah (spiritual level), and that is what "this" points to.

כמו זה הדבר שהוא דבר ברור אספקלריא המאירה שנתנבא בה מרע"ה.

Like "this is the thing" — a clear matter, the shining lens (aspaklaria ha-me'irah) through which Moshe Rabbeinu prophesied.

The word "this" denotes total clarity; Moshe alone prophesied through a clear, unclouded lens, whereas other nevi'im saw through a dim one.

וכתיב מסיני בא כו'. משעיר כו' פרשנו ד' בחי' אלו נגד ד' פירושים פרד"ס שבתורה.

And it is written, "He came from Sinai... from Se'ir..." — we explained these four aspects as corresponding to the four interpretations, PaRDeS, within the Torah.

The four place-names in the verse correspond to the four levels of Torah interpretation: Pshat, Remez, Drush, and Sod.

ומקודם פשט התורה שמוכרח להיות לבנ"י שע"ז נברא העולם אכן האומות רודפים לבנ"י כמ"ש תחת אהבתי כו'.

And first there is the pshat (plain level) of the Torah, which must belong to Bnei Yisrael, for the world was created for this; yet the nations pursue Bnei Yisrael, as it is written, "In return for my love..."

The plain level of Torah is the foundation for which the world was made and belongs by right to Bnei Yisrael, which is precisely why the nations rise up against them in hatred.

ומכח זה התנגדות זוכין בנ"י עוד למדריגות גבוהים עוד שבאין לבחי' סוד והוא מדריגת אש דת כו'.

And through the strength of this opposition, Bnei Yisrael merit even higher levels, reaching the aspect of Sod (the secret), which is the level of "fiery law" (eish das).

The very pressure of the nations' opposition lifts Bnei Yisrael to the deepest, fiery, hidden dimension of Torah.

והבן כי קצרתי:

Understand this, for I have been brief.

The Sefas Emes signals that he has compressed a much larger idea and leaves the reader to expand it.

Summary: The blessing of Moshe is the Torah itself, which he embodied and bequeathed to Bnei Yisrael across the four levels of PaRDeS; though the nations contend over the plain Torah that rightfully belongs to Klal Yisrael, that very opposition raises Bnei Yisrael to the deepest fiery secret of Torah.