The second chapter of Zechariah has been a comfort to many Christians all through their lives. Here is a remnant who got back to Jerusalem, and the temple is about to be built. The Lord encouraged them to build it.
I lifted up mine eyes again, and looked, and behold a man with a measuring line in his hand.... To measure Jerusalem, to see what is the breadth thereof, and what is the length thereof And, behold, the angel that talked with me went forth, and another angel went out to meet him, and said unto him, Run, speak to this young man, saying, Jerusalem shall be inhabited as towns without walls for the multitude of men and cattle therein. (vv. 1-4.)
Notice the next verse: "For I, saith the Lord, will be unto her a wall of fire round about, and will be the glory in the midst of her." The Lord would be a wall of fire to keep evil out, and glory in the midst of her in which to rejoice. The point is, faith is sustained in the day of ruin by looking onward to the day of glory. When things are dark, God gives that ray of light to cheer.
We should get our eyes on the coming glory and press on (see Phil. 3). Not one thing will ever fail on God's part. The only responsibility of the saint of God is to see that his own walk is according to God's mind. If the ruin comes in, the heart is sustained by looking onward to the day of glory.