What is "Bel"?
Rashi: It is the idolatry of Bavel.
What will be the punishment of "Bel"?
Radak: They will break it and carry away its gold. And so it says in Yeshayah (46:1) "Kara Bel Kores Nevo."
What is "Bil'o"?
Rashi: All dwellers of the land were under it (it is as if it swallowed the entire world).
Radak: "V'Hotzeisi Es Bil'o mi'Piv" is a metaphor. They used to bring Menachos to it. This is like "Chayil Bala va'Ykienu" (Iyov 20:15).
What is "Yinharu"?
Rashi: It is to gather, like "v'Naharu Elav Kol ha'Goyim" (Yeshayah 2:2), like the water of all Naharos (rivers), which go to (are gathered in) the sea.
Radak: It is rushing to an object, like "v'Naharu Elav Kol ha'Goyim" (Yeshayah 2:2).
Why does it say "Gam"?
Radak: The wall was strong and thick - "Chomas Bavel ha'Rechavah" (58).
Did the wall fall by itself?
Radak: [The enemy] toppled it.