Zechariah 1:20 (b) Here is an agency GOD uses to tear down or to build up His work among men. The four horns mentioned in the previous verses may indicate the great Gentile kingdoms of Babylon, Persia, Greece and Rome. They of course were very destructive to Israel. Probably the Lord sent along the four carpenters to repair the damage done by the four horns. GOD always has a remedy for every difficulty and defeat.