The priesthood of Joshua signifies the priesthood of the nation of Israel for the nations for God. The lampstand of gold signifies the shining testimony of the nation of Israel toward the nations for God. God had chosen Israel to be a nation of priests (Exo. 19:6). God's intention was to use the nation of Israel as a priesthood to bring the nations to God that they might enter into God's presence to be enlightened, exposed, dealt with, and transfused by God with the divine riches. In addition, the priests were to teach the nations how to worship God and serve God. In order for the priests to do this, they would have to be familiar with God's law and His regulations. In addition to being a nation of priests, Israel was also to be a testimony standing for God. Therefore, in chapter three we have the priesthood, and in chapter four, the lampstand.
The angel who spoke with Zechariah roused him and said to him, "What do you see? And I said, I see, and behold, there is a lampstand all of gold with its bowl on top of it and its seven lamps upon it, with seven pipes for each of the lamps on top of it" (Zech. 4:2). The lampstand here signifies the embodiment of the Triune God.
The substance of the lampstand is gold, signifying the Father as its source and nature.
The form of the lampstand being a lampstand signifies the Son as the embodiment.
The expression of the lampstand is the seven lamps, signifying the Spirit as the sevenfold intensified expression.
The supply of the lampstand is the seven pipes for each of the lamps, signifying the sevenfold intensified Spirit of God as its bountiful supply (Phil. 1:19b).
First, Christ is the lampstand as the testimony of God (Exo. 25:31-39). Second, the nation of Israel is the lampstand as the testimony of God. Third, the local churches are the lampstands as the testimony of Christ (Rev. 1:12, 20b).