In verses 6 and 7 Christ as the Angel of Jehovah testified to Joshua. Here testified actually means "charged."
In His charge to Joshua, Christ as the Angel of Jehovah said, "Thus says Jehovah of hosts, If you will walk in My ways and if you will keep My charge, then you will both judge My house and keep My courts, and I will grant you to walk among these standing here." With respect to this charge, I would like to point out that in God's administration among the people of Israel, there were three offices: the priests, the kings, and the prophets. The responsibility of the high priest was to be clear about the matters concerning God's people and to bring these matters to God and wait on God until He enlightened him and gave him a definite answer. The enlightenment and the answer came through the Urim and the Thummim. The high priest, therefore, received God's decision and instruction regarding various situations, and then he passed on the decision and instructions to the king, who was responsible in God's administration to carry them out. We may compare the priest's duty to that of those in the legislative branch of the government, and the king's duty to that of the president in the executive branch. Just as the president is responsible for enforcing the laws passed by the legislature, so the kings in Israel were responsible for carrying out the instructions received from God by the high priest. However, sometimes both the priests and the kings were weak and inadequate. At such times God would raise up the prophets to speak for Him. Here in Zechariah both Joshua the high priest and Zerubbabel the king were rather weak and somewhat discouraged. Therefore, God used Zechariah the prophet to speak for Him and to strengthen and encourage Joshua and Zerubbabel. The vision in chapter three is related to God's decision concerning Joshua. As we will see, the vision in chapter four is related to Zerubbabel and to his responsibility to carry out God's decision to continue and complete the rebuilding of the temple.
In verses 8 through 10 Christ as the Angel of Jehovah strengthened Joshua with Zerubbabel the governor of Judah (Hag. 1:1, 14).
Verse 8 says, "Hear then, Joshua the high priest, you and your fellows who sit before you—for they are men of symbol—for, behold, I am bringing forth My Servant, the Shoot." This refers to Zerubbabel who is a type of Christ as the Servant of Jehovah, the Shoot of David, in His humanity and royal faithfulness (Zech. 6:12).