Charles Ellicott Commentary Zechariah 3:4

"And he answered and spake unto those that stood before him, saying, Take the filthy garments from off him. And unto him he said, Behold, I have caused thine iniquity to pass from thee, and I will clothe thee with rich apparel." — Zechariah 3:4 (ASV)

Those that stood before him is an expression meaning courtiers and counselors (1 Kings 13:6–8); and here, it probably means angels of a lower rank than the “angel of the Lord.”

Your iniquity — i.e., of you, and of the people whose representative you are.

And I will clothe you. —Better, and I clothe you. The tense is “the aorist of immediate past.” (Compare Greek ἐδεξάμην, “I welcome.”) The Septuagint changes the mood and person, and renders καὶ ἐνδύσατε αὐτὸν ποδήρη, “and clothe you him with a long garment.”

Change of garments. —The word simply means garments different from the filthy ones in which he was clothed before: clean ones, in fact. (See next verse.) The figure seems to be borrowed from Isaiah 61:10: “He hath clothed me with garments of salvation, He hath clothed me with a robe of righteousness.” That it does not mean “festal garments” is shown by the ordinary word for “garments” being used in Zechariah 3:5.