It’s NOT by MIGHT nor by POWER but by HIS SPIRIT: This is the word of the Lord to Zerubbabel: “Not by might nor by power, but by My Spirit,” says the Lord of hosts. “Who are you, O great mountain? Before Zerubbabel you shall become a plain!" (Zech 4:6-7)
As governor of Judah, Zerubbabel was ultimately responsible for rebuilding the Temple in Jerusalem, which had began in earnest ten years ago (Ezra 5:1, 2; Hag. 1:14), but this work was currently stalled. It appeared that all his efforts had failed. However, God wanted Zerubbabel to understand that He (Himself) was his strength and would supply everything that was needed to accomplish the task to which He had called him. Though physical effort and objects were involved in the work, this work was actually spiritual and could be accomplished only through the power of the Holy Spirit. The ‘great mountain’ mentioned was a figurative reference to the great obstacles the people faced in rebuilding the temple (Ezra 5:3–17).
Even today, God’s people are told not to depend on military power and foreign alliances to accomplish their calling (Isaiah 31:1–3; Psalms 20:7–9). Ultimately, brute force is not the way that God accomplishes His work. God’s Spirit is the empowering agent of His activity (v. 6). Human energy, creativity, planning, and thinking have value, but they count little without spiritual strength (Ezek. 37:1–14). God’s grace can move the biggest mountains (obstacles) one faces, reducing them to easily traveled plains (v. 7). Zerubbabel saw examples of this in his own day when God graciously removed a number of obstructionists who stood in the way of the temple’s completion (Ezra 4:1–6:12).
Nations and churches truly prosper, not as a result of their erudition or financial resources, but only because God’s power is operative. Let’s understand that our weakness is no hindrance to God, nor is our strength an aid to God. God ultimately works out His purposes in our lives by the power of His Spirit (Hos. 1:7; 2 Cor. 4:7, 12:8-9).
"I can do all things through Christ who strengthens me." (Phil 4:13)