Reawakening The Sinai Voice
בפסוק א"ה האלה דבר ה' אל כל קהלכם
On the pasuk "These words Hashem spoke to your entire assembly" (Devarim 5:19).
The Sfas Emes opens by citing the pasuk in which Moshe Rabbeinu describes how Hashem spoke the words of the Aseres HaDibros to the whole assembly of Bnei Yisrael.
כל מיותר לכאורה
The word "entire" appears, at first glance, to be superfluous.
He notices a difficulty: the word "entire" seems unnecessary, since saying "your assembly" would already convey the point.
וי"ל על כל הקהילות שמתאספין בנ"י תמיד כמ"ש חז"ל עשרה שיושבים ויש ביניהם ד"ת שכינה שרויה ביניהם
One can explain that it alludes to all the gatherings in which Bnei Yisrael are constantly assembling, as Chazal said: when ten sit together and there are words of Torah among them, the Shechinah rests among them.
He resolves it by saying the word hints at every future gathering of Bnei Yisrael, drawing on Chazal's teaching that the Shechinah rests wherever ten sit and learn Torah together.
וכ"ז בא בשעת מתן תורה כמ"ש הקהל כו' ואשמיעם את דברי הי' הכנה והארה שכל התאספות של בנ"י לדורי דורות יכולין לעורר אותן הדברים
And all of this came about at the time of Mattan Torah, as it is written "Assemble the people... and I will let them hear My words" (Devarim 4:10) — a preparation and an illumination, such that every gathering of Bnei Yisrael throughout all generations is able to awaken those very words.
The original Mattan Torah was meant as a preparation and a spiritual illumination that empowers every later gathering of Bnei Yisrael to reawaken those same divine words.
כמ"ש קול גדול ולא יסף ולא פסק
As it is written "a great voice that did not cease" (Devarim 5:19), meaning it never stopped.
He brings proof from the pasuk that the voice at Sinai was "a great voice that did not cease" — it continues to resonate and never came to an end.
וכמו שעשרה מאמרות הוא יסד ובנין על כל הבריאה
And just as the ten utterances are the foundation and the structure upon which all of Creation stands,
He draws a parallel: just as the ten maamaros with which Hashem created the world are the foundation of all of Creation,
כן עשרת הדברות הם יסוד ובנין על כל הנהגת בנ"י
so too the Aseres HaDibros are the foundation and the structure upon which all the conduct of Bnei Yisrael stands.
so too the Aseres HaDibros serve as the foundation and framework for the entire way of life of Bnei Yisrael.
רק ההפרש שמאמרות היו ברצון הבורא ית' בלבד אבל הדיברות היו ע"י הכנת בנ"י שהקדימו נעשה ומס"נ על כבוד שמו ית'
The only difference is that the utterances came about through the will of the Borei, may He be blessed, alone, whereas the Dibros came about through the preparation of Bnei Yisrael, who placed "we will do" before "we will hear" and were ready to give up their lives for the honor of His Name, may He be blessed.
The difference between them is that Creation came solely from Hashem's will, while the Dibros required the active preparation of Bnei Yisrael, who declared "naaseh" before "nishma" and were willing to be moser nefesh for Hashem's honor.
לכן גם עתה מעוררין זה הכח ע"י הכנה למטה
Therefore even now we awaken this very power through preparation here below.
Because the Dibros depend on our preparation, even today we can reawaken their power through our own readiness and avodah from below.
וכמו כן בנפש אדם עצמו כשמאסף כל הכחות להשתעבד אליו ית' הוא בכלל כל קהלכם
And likewise within the soul of a person himself: when he gathers together all his faculties to subjugate them to His service, may He be blessed, he too is included in "your entire assembly."
He applies this inwardly as well: when a person gathers all his inner faculties and dedicates them to serving Hashem, he himself becomes a "complete assembly" in miniature.
וכן איתא מנין שאפי' א' יושב ושונה כו':
And so it is taught: from where do we know that even one who sits and learns alone, the Shechinah is with him, etc.
He closes with Chazal's teaching that the Shechinah rests even upon a single individual who sits and learns Torah by himself.
Summary: The Sfas Emes asks why the pasuk in Vaeschanan stresses that Hashem spoke to your "entire" assembly. He answers that the word hints at every future gathering of Bnei Yisrael, for the great voice of Mattan Torah never ceased but remains a wellspring of illumination that each generation can reawaken through Torah learned together. He compares the Aseres HaDibros to the ten utterances of Creation: just as the maamaros are the foundation of the world, the Dibros are the foundation of the entire conduct of Bnei Yisrael. The crucial difference is that Creation flowed from Hashem's will alone, while the Dibros depended on the preparation of Bnei Yisrael, who placed naaseh before nishma and were ready to be moser nefesh for His honor — which is why our own preparation from below still draws down that power today. Finally, this applies within each person: when one gathers all his faculties to serve Hashem, he becomes a complete "assembly" upon whom the Shechinah rests, just as Chazal teach it rests even upon a lone individual learning Torah.