Jamieson, Fausset and Brown on 1 Kings 22:11

11. Zedekiah the son of Chenaanah made him horns of iron--Small projections, of the size and form of our candle extinguishers (worn in many parts of the East as military ornaments), were worn by the Syrians of that time, and probably by the Israelite warriors also. Zedekiah, by assuming two horns, personated two heroes, and, pretending to be a prophet, wished in this manner to represent the kings of Israel and Judah in a military triumph. It was a symbolic action, to impart greater force to his language (see De 33:17); but it was little more than a flourish with a spontoon [Calmet, Fragments].