Charles Ellicott Commentary Zechariah 12:4

"In that day, saith Jehovah, I will smite every horse with terror, and his rider with madness; and I will open mine eyes upon the house of Judah, and will smite every horse of the peoples with blindness." — Zechariah 12:4 (ASV)

Horse — namely, of the enemy. (Compare Deuteronomy 28:28 with Deuteronomy 30:7.)

Open my eyes. — Compare 1 Kings 8:29.