Bel; i.e. Merodach, the patron deity of Babylon (see on Jeremiah 50:2). Swallowed up. An allusion to the myth mentioned above (see Jeremiah 51:34). That which Bel, i.e. Babylon, has "swallowed up" is not only the spoil of the conquered nations, but those nations themselves.
Yea, the wall of Babylon shall fall; literally, is fallen (is as good as fallen). The famous wall of Babylon (comp. Jeremiah 51:58) is described by Herodotus. From this clause down to the first half of Jeremiah 51:49 is omitted in the Septuagint.