Earning Eretz Yisrael Ourselves

במדרש שמע ישראל אתה עובר כו' קלקלתם נעשה הזהרו בנשמע כו'

The Midrash teaches on the verse "Shema Yisrael, you are crossing over today the Yarden" (Devarim 9:1) and continues: when you spoiled matters through the sin of the Golden Calf with the words "Naaseh, we will do" (Shemos 24:7), Hashem warned you to be careful with "Nishma, we will hear."

The Sfas Emes opens with a Midrash that links the two terms "Naaseh" and "Nishma": once Bnei Yisrael damaged the level of "Naaseh" (doing) by the sin of the Golden Calf, they were directed instead to safeguard "Nishma" (hearing/accepting).

נראה הרמז כאן שאם לא הי' מתקלקל נעשה היו זוכין בעצמם לירושת הארץ

It appears that the hint here is that, had "Naaseh" not become spoiled, Bnei Yisrael would have merited the inheritance of the Land through their own selves.

The point he draws out is that if the level of "Naaseh" had remained intact, Bnei Yisrael would have been worthy of the Land on their own standing, without needing to lean on anything else.

כי נשמע הוא רק לקבל ירושת האבות כמ"ש לא בצדקתך

For "Nishma" serves only to receive the inheritance of the Avos, as it is written, "Not through your righteousness" (Devarim 9:5) — meaning, you take the Land not by your own merit but as the bequest of your fathers.

"Nishma" by contrast only secures the Land as the inheritance of the Avos, which is why the Torah stresses that the Land is given not because of one's own righteousness but as a bequest from the fathers.

וכל מגמתו של מרע"ה להיות בנ"י מתוקנים בעצמם לירושת הארץ ואז הי' הוא מכניסם לארץ ולא הי' עוד גלות:

And the entire aim of Moshe Rabbeinu was that Bnei Yisrael should be set right within themselves, fit for the inheritance of the Land through their own merit, and then he himself would have brought them into the Land, and there would no longer have been any galus.

Moshe Rabbeinu's whole goal was to make Bnei Yisrael complete in their own avodah so they would deserve the Land on their own merit; had that been achieved, Moshe himself would have led them in and galus would never have come into being.

Summary: The Sfas Emes builds on a Midrash contrasting "Naaseh" (we will do) and "Nishma" (we will hear). He explains that had the level of "Naaseh" not been damaged through the sin of the Golden Calf, Bnei Yisrael would have merited the inheritance of Eretz Yisrael through their own avodah and standing. As it was, they could only inherit the Land through "Nishma" — as the bequest of the Avos, "not through your righteousness." Moshe Rabbeinu's deepest aspiration was that Bnei Yisrael be made complete within themselves, fit for the Land by their own merit. Had that been realized, Moshe himself would have brought them in and there would never have been any galus.