At some point, visitors from the Jewish colony in Babylon arrived with gifts for the Jews in Jerusalem. God specified that part of this gift was to belong to Him, and that part was to be made a crown for Joshua, the High Priest.
The passage takes us a bit by surprise. We would expect Zerubbabel to be crowned king; after all, it is he who is of David’s line, not Joshua.
But purpose of this “word of the Lord” (vs. 9) is not really to crown Joshua king. After all, the crown does not stay with Joshua, but becomes a part of the artifacts in the temple. Secondly, the oracle speaks of a time to come because God says “this will happen” if you dilligently obey the Lord.
This word of the Lord looks forward to a day when the work of king and priest becomes united, and is the clearest text in the Old Testament of God’s intent.
Jesus, of course, becomes the fulfillment of this promise as both king and priest.
We are reminded as the chapter comes to a close that God’s promises are conditional: conditional on the Lord’s people being faithful to the leading of God. God’s promises do not just take place. They take place when God is ready, but also, when His people are ready.