The vision in Zechariah 3.1-5 offers a clear symbolic gospel message:

Then he showed me Joshua the high priest 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 a brand plucked from the fire?” Now Joshua was standing before the angel, clothed with filthy garments. And the angel said to those who were standing before him, “Remove the filthy garments from him.” And to him he said, “Behold, I have taken your iniquity away from you, and I will clothe you with pure vestments.” 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 garments. And the angel of the LORD was standing by.

Satan stands ready to accuse because the Israelites have indeed done evil in the sight of the LORD; they are not holy like their God.  The filthy garments of Joshua the priest, the representative of the people, testify further to their defilement.   Joshua and the people of Israel deserve condemnation.

But, God steps in.  He rebukes Satan even before an accusation can be made.  God’s saving grace plucks Joshua from the fire of hell.  Joshua’s filthy rags are removed; he is clothed with pure vestments and a clean turban.  His iniquity is taken away.  Their forgiveness is not earned; it is a gift from their merciful Father.

Still to come, in verse 8, God promises the people that his servant, the Branch, will fully resolve the iniquity of the people.  The arrival of Jesus was foretold five centuries before He appeared.