6:9-15 Some Jews from Babylon brought an offering to the house of God. Those who cannot forward a good work by their persons, must, as they are able, forward it by their purses: if some find hands, let others fill them. Crowns are to be made, and put upon the head of Joshua. The sign was used, to make the promise more noticed, that God will, in the fulness of time, raise up a great High Priest, like Joshua, who is but the figure of one that is to come. Christ is not only the Foundation, but the Founder of this temple, by his Spirit and grace. Glory is a burden, but not too heavy for Him to bear who upholds all things. The cross was His glory, and he bore that; so is the crown an exceeding weight of glory, and he bears that. The counsel of peace should be between the priest and the throne, between the priestly and kingly offices of Jesus Christ. The peace and welfare of the gospel church, and of all believers, shall be wrought, though not by two several persons, yet by two several offices meeting in one; Christ, purchasing all peace by his priesthood, maintaining and defending it by his kingdom. The crowns used in this solemnity must be kept in the temple, as evidence of this promise of the Messiah. Let us not think of separating what God has joined in his counsel of peace. We cannot come to God by Christ as our Priest, if we refuse to have him rule over us as our King. We have no real ground to think our peace is made with God, unless we try to keep his commandments.

Zec 6:9-15. Ninth Vision. The Crowning of Joshua.

The double crown is placed on Joshua's head, symbolizing that the true priesthood and the kingdom shall be conferred on the one Messiah. Compare Heb 6:20; 7:1-21, on Melchisedek, who similarly combined the kingdom and priesthood as type of Messiah.