Emunah As Path To Emes
במדרש גדול העונה אמן לפני הקב"ה כו'
In the Midrash: "Greater is one who answers Amen than the Holy One, Blessed is He" who makes the blessing, and so on.
The Sfas Emes opens with the Midrash that one who answers Amen is, in a sense, greater than the one who actually recites the blessing.
כי הנה דור המדבר היו כולם בבחי' אמת לאמיתו
For behold, the generation of the wilderness were all on the level of absolute truth, truth in its truest sense.
The generation that received the Torah in the desert lived directly with absolute emes, seeing with full clarity.
ודור באי הארץ הי' בבחי' אמונה אספקלריא שאינה מאירה ואין האמת מבורר וצריכין להאמין וע"י האמונה לזכות אל האמת
But the generation that entered the Land were on the level of emunah (faith) — the dim, unclear lens through which one does not see directly, where the emes is not clearly evident, and one must believe; and through that emunah one merits to come to the emes.
The generation that entered the Land, by contrast, lived on the level of emunah — a clouded lens where the emes is hidden, so they had to believe in order to eventually reach the emes itself.
וזה הי' עניית האמן בכניסת א"י
And this was the matter of answering Amen upon entering Eretz Yisrael.
This is precisely why answering Amen took on such importance specifically at the moment of entering Eretz Yisrael, the realm of emunah.
דאיתא בגמ' בא דוד והעמידן על אחת עשרה כו' בא חבקוק והעמידן על אחת וצדיק באמונתו יחי'
For it is brought in the Gemara (Makkos 24a): Dovid HaMelech came and established them — the six hundred and thirteen mitzvos — upon eleven principles, and so on; Chavakuk came and established them upon one, as it says, "and the tzaddik shall live by his emunah" (Chavakuk 2:4).
The Gemara teaches that Dovid HaMelech reduced all the mitzvos to eleven principles, and Chavakuk to the single foundation that a tzaddik lives by his emunah — showing emunah is the root that contains everything.
ומסתמא הי"א דברים הם מכוונים מול הי"א ארורים שבפרשה שהם המחשכים את האמת וע"י קבלת י"א דברים אלו זוכין אל האמת
And presumably these eleven matters correspond to the eleven "arurim" (curses) in the parshah, which are the things that darken and obscure the emes; and through accepting these eleven matters one merits to reach the emes.
The Sfas Emes proposes that Dovid's eleven principles parallel the eleven curses in the parshah, since those curses represent the forces that darken the emes, and accepting these eleven matters is the avodah that brings one to clear truth.
ואח"כ מצאתי בס' רבינו בחיי ג"כ מזה
And afterward I found in the sefer of Rabbeinu Bachya likewise concerning this.
He notes that he later found support for this idea in the writings of Rabbeinu Bachya.
ופשוטי בנ"י שלא זכו לכל הי"א ע"י עניית אמן הי' להם חלק בזה הברית כמ"ש וצדיק באמונתו יחי':
And the simple folk among Bnei Yisrael, who did not merit to attain all eleven principles, through answering Amen had a portion in this covenant, as it says, "and the tzaddik shall live by his emunah" (Chavakuk 2:4).
Even the simple Jews who could not grasp all eleven lofty principles still shared in the covenant through the single act of answering Amen, for the tzaddik lives by his emunah — sincere faith alone grants a portion in the emes.
Summary: The Sfas Emes contrasts two generations: the dor hamidbar, who lived with absolute emes seen through a clear lens, and the generation entering Eretz Yisrael, who lived on the level of emunah, where the truth is hidden and must be believed in order ultimately to be reached. This is why answering Amen — the affirmation of faith — became central upon entering the Land. He links the Gemara's teaching that Dovid HaMelech distilled the mitzvos to eleven principles, and Chavakuk to the one foundation that "the tzaddik shall live by his emunah," with the eleven curses of the parshah, which represent the forces that darken the emes; accepting these eleven matters is the avodah that brings one to clarity of truth. Finding support in Rabbeinu Bachya, the Sfas Emes concludes that even simple Jews who could not attain all eleven lofty principles still gained a portion in the covenant through the single act of answering Amen, for sincere emunah itself is the path by which the tzaddik lives and reaches the emes.