The fourth of eight visions in Zechariah is of the High Priest of Zechariah's day on the Day of Atonement. The High Priest; Joshua, is viewed in the spiritual realm in God's Holy court. The court is presided over by an angel of the Lord. While only Joshua goes into the Holy Place in the physical world, it is Joshua and Satan who are before God in the spiritual realm.
The preparation for the Day of Atonement was quite involved. The High Priest needed to be fitted exactingly in his clothes. Each part of his attire was significant. It is peculiar to think that the clothing would be dirty or stained. An illustration of the clothing of the High Priest exhibits the care taken in dressing fittingly: