The 4 carpenters in Zechariah were sent to overcome/overpower the 4 horns that have kept the sons of Judah down. This may represent the overpowering of 4 aspects of society: finances, education, politics, and social (media/religion/sports etc.)
In any event these 4 powers that have taken over will be demolished by the 4 carpenters (in Hebrew builders/craftsmen/skilled warriors).
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