Charles Ellicott Commentary Zechariah 4:6

"Then he answered and spake unto me, saying, This is the word of Jehovah unto Zerubbabel, saying, Not by might, nor by power, but by my Spirit, saith Jehovah of hosts." — Zechariah 4:6 (ASV)

This ... word. —The vision is called “the word,” as being a symbolical prophecy . As the golden candlestick was placed in the holy place of the Tabernacle (and the Temple) before the LORD, as an everlasting statute for their generations on behalf of the children of Israel (Exodus 27:21), so did the congregation on whose behalf (or as a symbol of which) was the candlestick, require a sanctuary in which to let their light shine before the Lord, and from which it might shine before men.

This sanctuary Zerubbabel had founded, and his hands were to complete (Zechariah 4:9); but not by any merit or strength of his own or of Israel, but simply by the Spirit of the Lord of Hosts, which would revive the dry bones of the house of Israel, that they should live, and be placed in their own land (Ezekiel 37:11–14).