Declare ... publish - as if giving sentence from a tribunal.
Migdol ... Noph ... Tahpanhes - east, south, and north. He mentions the three other quarters, but omits the west, because the Chaldeans did not advance thither. These cities, too, were the best known to the Jews, as being in their direction.
sword shall devour round about thee - namely, the Syrians, Jews, Moabites, and Ammonites (see on Jer 48:1). The exhortation is ironical, as in Jer 46:4, Jer 46:9.