Merit Of The Avos
בפסוק א"ת בלבבך כו' וברשעת הגוים כו'
On the pasuk, "Do not say in your heart... it is because of the wickedness of these nations..." (Devarim 9:4).
The Sfas Emes opens with the pasuk in which Moshe Rabbeinu warns Bnei Yisrael not to attribute their entry into the Land to their own righteousness, but to the wickedness of the nations being dispossessed.
ותמוה דמסיים ברשעת הגוים כו'
This is puzzling, for the pasuk concludes with "because of the wickedness of these nations..."
He raises a difficulty: why does the pasuk conclude by pointing to the wickedness of the nations as the operative reason?
וי"ל כי כל המשפט תלוי בעמידת בנ"י ובוודאי אם היו בנ"י מתוקנים כראוי הי' נגמר מיד סאתם של הכנענים
We can explain that the entire judgment hinges upon how Bnei Yisrael stand. Surely, had Bnei Yisrael been properly set right as they ought to be, the measure of the sins of the Canaanites would have been brought to its full at once.
He answers that everything turns on the spiritual standing of Bnei Yisrael; had they been fully set right, the nations' sins would have reached their full measure immediately, hastening their downfall.
לכן א"ת בצדקתי וברשעת כו' כי לפי מעשיכם עדיין לא נגמר סאתם של הגוים
Therefore the Torah says, "Do not say it is because of my righteousness... and because of the wickedness..." (Devarim 9:4), for according to your deeds the measure of the nations was not yet brought to its full.
Thus the pasuk teaches that it was not yet by virtue of their own deeds that the nations' measure was filled, since their own conduct had not yet earned it.
רק ע"י שלבנ"י הקב"ה מצרף מחשבה טובה למעשה
Rather, it came about only because, for Bnei Yisrael, the Holy One, Blessed is He, joins a good thought to the deed itself.
Rather, it happened because Hashem credits Bnei Yisrael by joining their good intention to the actual deed, granting them more than their plain actions deserve.
והוא באמת ע"י זכות אבות פי' שעצם בנ"י טוב בכח האבות לכן כשבוחרין בדרכיהם ועושים כמעשיהם
And this is truly through the merit of the Avos; that is, the very essence of Bnei Yisrael is good, by virtue of the power of the Avos. Therefore, when they choose the ways of the Avos and act in accordance with their deeds,
This added merit flows from the merit of the Avos, for the inner essence of Bnei Yisrael is good through the power of the Avos; so when they walk in the Avos' ways, that essence is activated.
מעשיהם לא אמרו רק כמעשיהם
the pasuk does not say "their very deeds," but rather "like their deeds" (Devarim 9:5) —
He notes a precise reading of the pasuk: it does not say Bnei Yisrael's deeds are identical to the Avos' deeds, but only that they are "like" them.
שיש קצת דמיון
meaning that there is some measure of resemblance to them.
This means only a partial resemblance to the deeds of the Avos is required for the merit to take effect.
מיד מתעורר להם מעשי אבות ועי"כ מתמלא סאתם של הגוים ג"כ כנ"ל:
At once the deeds of the Avos are awakened for them, and through this the measure of the sins of the nations is likewise brought to its full, as explained above.
Even that partial resemblance suffices to awaken the merit of the Avos, which in turn brings the nations' measure of sin to its full completion, as explained above.
Summary: The Sfas Emes addresses the puzzle in Eikev of why Moshe Rabbeinu attributes Bnei Yisrael's inheritance of the Land to the wickedness of the nations rather than to their own merit. He explains that the entire judgment hinges upon the spiritual standing of Bnei Yisrael: had they been fully set right, the nations' measure of sin would have been completed at once. Since their own deeds had not yet earned this, the Holy One, Blessed is He, instead joins their good thought to their deed, drawing on the merit of the Avos that lies in the very essence of Bnei Yisrael. The pasuk hints at this by saying their conduct is only "like" the deeds of the Avos, requiring merely a partial resemblance. Even that small likeness awakens the merit of the Avos, which then brings the nations' measure of sin to its full completion.