Charles Ellicott Commentary Zechariah 6:1

"And again I lifted up mine eyes, and saw, and, behold, there came four chariots out from between two mountains; and the mountains were mountains of brass." — Zechariah 6:1 (ASV)

And I turned ... eyes. —Better, And again I lifted up my eyes (Zechariah 4:1; Zechariah 5:1; Zechariah 8:3).

There came. —Better, coming forth. The prototypes of these two mountains were, no doubt, the Mount of Olives (Zechariah 14:4) and Mount Zion, between which lies the Valley of Jehoshaphat, where the Lord judges (such is the meaning of the name) the nations (Joel 3:2 and following). But the mountains themselves were visionary, and are represented as of brass, to denote, according to some, the immovable firmness of the place where the Lord dwells, and where He has founded His kingdom.