So he said to me, “This is the word of the LORD to Zerubbabel: Not by might nor by power, but by My Spirit, says the LORD of Hosts. — Zechariah 4:6

Not by might nor by power, but by My Spirit,' says the Lord. That's the death blow to every scheme of self-reliance in the christian life. God chose the weak things to shame the strong so nobody can boast. The wind of the spirit blows where it wishes, and new birth doesn't come from human will or effort. Whatever God builds, he builds through his spirit. Our part is to lean into him and trust the work to the one who finishes what he starts.