Grievous revolters... — Literally, rebels of rebels, as a Hebraism for the worst type of rebellion.
Walking with slanders. — The phrase was a common one (Leviticus 19:16; Proverbs 11:13; Proverbs 20:19), and pointed to the restless eagerness of the tale-bearer to spread his falsehoods. (Comp. 1 Timothy 5:13, “wandering about... idle tattlers.”)
Brass and iron. — Base metals serving for vile uses, no gold or silver in them. The imagery, which carries on the thought of the previous verse, had been made familiar by Isaiah (Isaiah 1:22; Isaiah 1:25), and was reproduced afterwards by Ezekiel (Ezekiel 22:18-22) and Malachi (Malachi 3:3).
Corrupters. — Better, workers of destruction.