What is the meaning of "Achlu va'Yishtachavu Kol Dishnei Aretz"?
Rashi: The verse should be re-arranged. The humble will consume all Dishnei Aretz, and bow to Hashem with Hallel and thanks for the good. Dishnei Aretz is the good (Chelev) of the land. All the land will see this, and repent.
Radak citing his father: The nations that will repent to Hashem, that they were fat and fresh, so they will be now. Hashem will accept their Teshuvah, and they will eat and bow to Him and thank Him for all the good.
Radak citing Ibn Ezra: Dishnei Aretz are those who enjoy eating all pleasures in this world. They will not have pleasure in the world to come. Refer to 21:30:2:3.
Malbim: Dishnei Aretz, whose entire engagement is to fatten their bodies and indulge them like fattened calves, they ate until their stature bowed and bent due to filling the stomach. Fattening their bodies will not help - in the future, their bodies will be worms!
What is the meaning of "Lefanav Yichre'u Kol Yordei Afar v'Nafsho Lo Chiyah"?
Rashi: All the dead Resha'im will bow from Gehinom, but He will not have mercy on them to revive their souls from Gehinom.
Radak citing his father: However, some Goyim, Hashem will not accept their Teshuvah, i.e. those who killed Yisrael. They descend to Gehinom, and Hashem will not revive even one of them "v'Nikeisi Damam Lo Nikeisi" (Yo'el 4:21). One can pay for all the evils he did to Yisrael - "Tachas ha'Nechoshes Avi Zahav" (Yeshayah 60:17) - but one cannot pay for spilling human blood.
Radak citing Ibn Ezra: Those who enjoy eating all pleasures in this world, at the end of their days they will bow in front of the angel that gathers their Ru'ach 1 , and not one of them will be able to revive his soul; they will perish in the world to come. It is the opposite of the humble, about whom it says "Yechi Levavchem Yachad" (verse 27).
Radak (32): Notzrim erred, and say that this refers to their savior. He did not save himself; rather, he accepted to be killed to save those who descend to Gehinom. If so, why did he say "Keli Keli Lamah Azavtani" (2)?! He did not want to be saved! And why can't he save himself? Why did he mention "Tehilos Yisrael", and say that they praise and honor Hashem, if they afflicted him? If he had only one Father, who are "Avoseinu" (plural - verse 5)? Who are his brothers (verse 23)? Would G-d say about Himself "I am a worm" (verse 7)?!
Malbim: On the day of death, when they will be judged in front of Hashem, will bow those who did not do anything that their souls will endure eternally; they engaged only in their bodies, which now descend to the earth.
Radak (citing Nidah 30b): "Ki Li Sichra Kol Berech" (Yeshayah 45:23) refers to the day of death.
Why does it say "Yichre'u" (plural) and "v'Nafsho" (singular)?
Rashi: It refers to the Nefesh of each one.
Why does it say "Lo Chiyah"?
Rashi: This is like "Lo Yichyeh." Chazal (Semachos d'R. Chiya 4:2, Bamidbar Rabah 14:22) expounded that one receives Pnei ha'Shechinah before he dies.
