28. grievous revolters—literally, "contumacious of the contumacious," that is, most contumacious, the Hebrew mode of expressing a superlative. So "the strong among the mighty," that is, the strongest (Eze 32:21). See Jer 5:23; Ho 4:16.
walking with slanders—(Jer 9:4). "Going about for the purpose of slandering" [Maurer].
brass, &c.—that is, copper. It and "iron" being the baser and harder metals express the debased and obdurate character of the Jews (Isa 48:4; 60:17).