The Pulpit Commentary - Zechariah 1:18
I lifted up mine eyes, and saw. This vision is closely connected with the former. The prophet had been told that the hostile nations should be punished and scattered; he now is shown this threat being executed. Four horns, belching to four beasts but dimly seen or wholly invisible. Horns are symbols of strength and power (comp. Psalms 75:4 , Psalms 75:5 ; Daniel 8:3 ; Amos 6:13 ). Here they mean powers hostile to Israel, and the number "four" (the symbol of completeness) points to... read more
John Calvin's Commentary on the Bible - Zechariah 1:21
Verse 21 And who are these smiths? They are also horns; for they all wish to destroy as much as they can the Church; but God does not permit them; on the contrary he excites them to mutual wars to destroy one another. Though then all these are horns, ready to assault the Church, and though it appears evident from the comparison that they are as it were furious and vicious bulls, and as much as they can unite together to scatter the Church, yet God gives hammers to two or three of them, and bids... read more