Shared Merit Through Arvus
במדרש תנחומא כולכם
In the Midrash Tanchuma on the verse "all of you" (kulchem).
The Sfas Emes opens by citing the Midrash Tanchuma's teaching on the word "all of you" at the start of the parsha.
כולכם ערבים זה בזה צדיק א' בכם בזכותו כולכם עומדין כו'
"All of you" — you are guarantors one for another; even if there is one tzaddik among you, in his merit all of you stand, and so on.
The Midrash explains that Bnei Yisrael are guarantors for one another, so that the merit of even a single tzaddik allows the whole nation to stand.
פי' כפי מה שמכניס אדם עצמו בזה הערבות לקבל כ"א על עצמו עונש כללות ישראל
The meaning is: according to how much a person enters himself into this arrangement of arvus (mutual responsibility), each one taking upon himself the punishment of Klal Yisrael as a whole,
He explains that the benefit one receives is proportional to how fully he enters into this bond of arvus, accepting upon himself responsibility for the whole nation.
עי"ז זוכין ג"כ לעמוד בזכות זה הצדיק שזה בא בזכות הערבות
through this he likewise merits to stand in the merit of that tzaddik — for that merit comes precisely through the arvus.
By taking on that shared responsibility, a person earns the right to be sustained by the tzaddik's merit, since that merit flows specifically through the channel of arvus.
ובאמת סטרא דקדושה נקודה קטנה כוללת הכל כי אין הפרש בין רב למעט
And in truth, on the side of kedushah, a single small point includes everything, for there is no difference between much and little.
In the realm of kedushah, even one small point contains the whole, because holiness is not measured by quantity — large and small are equal there.
לכן אם יש צדיק א' לפני השי"ת ניתקן ע"י הכל
Therefore, if there is even one tzaddik before Hashem Yisbarach, the whole is repaired through him.
Consequently, the presence of even a single tzaddik before Hashem is enough to bring repair to the entire Klal.
אך שצריכין להכניס עצמו בכלל ישראל ע"י הערבות ועי"ז יש לנו חלק במעשה הצדיק
But one must enter himself into the Klal of Yisrael through the arvus, and through this we have a share in the deed of the tzaddik.
But this works only if a person joins himself to Klal Yisrael through arvus; that connection is what gives him a portion in the tzaddik's good deeds.
לכן אמר הכתוב כי זה הרשע שמיציא עצמו מהכלל עליו חל העונשין אבל כלל בנ"י לא יכלו ח"ו
Therefore the verse says that this rasha, who removes himself from the Klal, upon him fall the punishments, but Klal Bnei Yisrael cannot be wiped out, chas v'shalom.
This is why the verse warns that the rasha who cuts himself off from the Klal bears the punishments alone, while the Klal as a whole can never be destroyed.
ומאוד צריכין לעשות כל המצות ומעש"ט בכלל בנ"י
And one must very much take care to perform all the mitzvos and good deeds (maasim tovim) as part of Klal Bnei Yisrael.
Therefore a person should be very careful to do all his mitzvos and good deeds specifically as part of Klal Bnei Yisrael, not as an isolated individual.
וגם צריכין לידע כי גם כל הדורות שלאחרינו הכל תלוי במעשינו
And one must also know that even all the generations that come after us, everything depends upon our deeds.
He adds that we must realize our deeds affect not only ourselves but all future generations as well.
לכן נאמר לא אתכם בלבדכם כו' וקשה למה אמר להם זה
Therefore it is said, "Not with you alone" (Devarim 29:13), and so on — and the difficulty is: why did he say this to them?
This explains the verse "Not with you alone" — and the Sfas Emes raises the question of why Moshe Rabbeinu needed to tell them this.
רק כדי שידעו כי בקבלת הברית שהם מקבלין עי"ז מזכין לכל הדורות הבאים
Rather, it was so that they should know that through the acceptance of the bris which they accept, they thereby bring merit to all the coming generations.
The answer is that they needed to know that by accepting the bris, they were drawing merit down upon every generation that would come after them.
וכן הוא גם עתה בכל מעש"ט שבישראל:
And so it is even now, with every good deed (maaseh tov) done among Yisrael.
And this remains true in our own day: every single good deed done within Klal Yisrael brings merit to all the generations to come.
Summary: On the words "all of you" at the opening of the parsha, the Sfas Emes builds on the Midrash Tanchuma's teaching that Bnei Yisrael are arevim (guarantors) for one another, so that the merit of even one tzaddik enables the entire Klal to stand. The key is that the more fully a person enters into the bond of arvus and accepts responsibility for the whole nation, the greater his share in the tzaddik's merit — for in the realm of kedushah a single small point contains everything, and large and small are equal. One who cuts himself off from the Klal, like the rasha of the parsha, bears his punishments alone, while Klal Bnei Yisrael as a whole can never be destroyed, chas v'shalom. From here the Sfas Emes explains the verse "Not with you alone": by accepting the bris, Bnei Yisrael drew merit down upon all future generations. And so it remains today — every good deed done within Klal Yisrael brings merit to all the generations yet to come.