Jeremiah 6:28

They are all grievous revolters, walking with slanders: they are brass and iron; they are all corrupters.

Grievous revolters - literally, contumacious of the contumacious - i:e., most contumacious, the Hebrew mode of expressing a superlative. So "the strong among the mighty" - i:e., the strongest (). See ; .

Walking with slanders - (). 'Going about for the purpose of slandering' (Maurer).

Brass ... - i:e., copper. It and 'iron' being the baser and harder metals express the debased and obdurate character of the Jews (, "Thy neck is an iron sinew, and thy brow brass." In the coming restoration of all things and of the Jews first, God promises, "For brass I will bring gold, and for iron I will bring silver," 60:17).