John Gill Commentary 1 Kings 22:11

"And Zedekiah the son of Chenaanah made him horns of iron, and said, Thus saith Jehovah, With these shalt thou push the Syrians, until they be consumed." — 1 Kings 22:11 (ASV)

And Zedekiah the son of Chenaanah made him horns of iron
Horns are emblems of power and might, and iron ones of greater strength still; the prophets sometimes made use of visible signs, to represent the things they prophesied of should come to pass, see (Isaiah 20:2Isaiah 20:3) (Jeremiah 27:2) , and the same method this prophet took:

and he says, thus says the Lord; imitating the true prophets: with
these you shall push the Syrians until you have consumed them :
Abarbinel thinks he had in view the blessing of Joseph by Moses, (Deuteronomy 33:17) where he is compared to a bullock with horns; and these said to be the ten thousands of Ephraim, and the thousands of Manasseh; and Ahab being of the tribe of Joseph, and ruling in Ephraim and Manasseh, the prophet chose to make use of this emblem for his encouragement.