Then he showed me the high priest Joshua standing before the angel of the LORD, and Satan standing at his right hand to accuse him. And the LORD said to Satan, “The LORD rebuke you, O Satan! The LORD who has chosen Jerusalem rebuke you! Is not this man a brand plucked from the fire?” Now Joshua was dressed with filthy clothes as he stood before the angel. The angel said to those who were standing before him, “Take off his filthy clothes.” And to him he said, “See, I have taken your guilt away from you, and I will clothe you with festal apparel.” And I said, “Let them put a clean turban on his head.” So they put a clean turban on his head and clothed him with the apparel; and the angel of the LORD was standing by. Then the angel of the LORD assured Joshua, saying, “Thus says the LORD of hosts: If you will walk in my ways and keep my requirements, then you shall rule my house and have charge of my courts, and I will give you the right of access among those who are standing here.
“Now listen, Joshua, high priest, you and your colleagues who sit
before you! For they are an omen of things to come: I am going to bring
my servant the Branch. For on the stone that I have set before Joshua,
on a single stone with seven facets, I will engrave its inscription,
says the LORD of hosts, and I will remove the guilt of this land in a
single day. On that day, says the LORD of hosts, you shall invite each
other to come under your vine and fig tree. - Zechariah 3
According to the New Oxford Annotated Bible, "The book of Zechariah is the longest and most obscure of the Minor Prophets."* No kidding! This isn't a very well known reading from the Bible, but that's a shame. It has all sorts of interesting imagery in it.
This Joshua, first of all, is not the same as the Joshua who "fit de battle of Jericho," but is rather a high priest of the temple at the time of its rebuilding following the Babylonian Exile. Here Joshua represents the holy tradition of Israel, being renewed and prepared for a celebration.
Yet still, the terms on which Joshua will continue in God's good graces are conditional: "if you will walk in my ways and keep my requirements." This is all God has ever asked, but the people have shown time and time again their inability to do even this much. It is the human condition: no matter how much we want to follow God's ways, we fail. We always fail.
But get ready. Here comes the Branch -- a reference to the "Root of Jesse," the royal descendant of David. The Branch will grow into a flowing vine to produce grapes for wine, or into a sturdy fig tree to produce fruit ... fruit worthy of repentance. And God will remove all our guilt in a single day.
* Gregory Mobley, "Zechariah," in the New Oxford Annotated Bible (New York: Oxford University Press, 2007), 1357.