Zechariah 4:6,7
'This is the word of the Lord to Zerubbabel saying, ‘Not by might nor by power, but by My Spirit,’ says the Lord of hosts. "What are you, O great mountain? Before Zerubbabel you will become a plain; and he will bring forth the capstone with shouts of 'Grace, grace to it!'
Governor "Zerubbabel" was to complete the building of Jerusalem, make the place habitable, and especially he was to reconstruct the Temple of God. The text is telling us that Zerubbabel will not complete this in his own might nor by his own power, but through the guidance of the Spirit of God.
Zerubbabel had a "mountain" of difficulties in his life, as we all do...and up to this point, he had been unable to do much about the task of rebuilding. God is saying through the angel (v.7), to him and to each one of us: have faith!
When God revels His will to us, our part is to act in faith and believe He will accomplish it through us.
The Truth
"Without faith it is impossible to please Him, for he who comes to God must believe that He is, and that He is a rewarder of those who diligently seek Him." (Hebrews 11:6)