What is "Midbar ha'Amim"?
Rashi: It is the Midbar in which Yisrael went for 40 years. And so it says "v'Holachtiha ha'Midbar" (Hoshe'a 2:16).
Radak: When I will take you out of the nations, I will not bring you to Yisrael until I judge you in Midbar ha'Amim. There I will exact My Mishpat from you, and eradicated the sinners that I find among you. It will be in a Midbar where there are no people and no passersby, lest the nations see your evil and rejoice over you.
Malbim #1: The land of the nations is called Midbar, for one does not find his needs there. It is like a Midbar for you. You will be far from settlement, separated from people who dwell in cities like flock that stray in the Midbar, lacking all food. They will not let you buy houses, fields and gardens, as if you dwell in the Midbar.
Malbim #2: From] every land that they will go in Galus, they will go in the Midbar of that land. Leaving at the set time will be like Yetzi'as Egypt. There was one Midbar, for you were in Galus in one land, [but future] there will be many Midbaros, of every nation.
Why does it say "v'Nishpateti Itechem Sham Panim El Panim"?
Radak: I will judge just between us, without an intermediary. The same applies to "va'Ydaber Hashem El Moshe Panim El Panim" (Shemos 33:11), I will make known your evil deeds, that you transgressed My Torah in Galus, and I will take My vengeance on you in the Midbar.
Malbim: You will recognize that the punishments are of Hashgachah, as if He speaks His Mishpatim with you face to face, like you saw and recognized His Hashgachah and punishments in the Midbar of Eretz Egypt. You will see the revelation of the Shechinah and Hashem's speech face to face, and He will debate with you about your sins, just like at the time of Yetzi'as Egypt you saw that Hashem's deed is awesome.
