"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." (Zechariah 2:5)
This beautiful promise applies explicitly to Jerusalem in the days to come when "all Israel shall be saved" (Romans 11:26). In the meantime, believers can appropriate it now as an evidence of God's great concern for all His people.
The safest, most secure place in all the world for one of Christ's servants is in the will of God. All around him is an invisible, but invincible, spiritual "wall of fire," both protecting and energizing him. As the psalmist said: "The angel of the Lord encampeth round about them that fear him, and delivereth them" (Psalm 34:7). Elisha's servant, fearful of the enemy host arrayed against them, was encouraged when his eyes were enabled to see, in answer to Elisha's prayer, that "the mountain was full of horses and chariots of fire round about Elisha" (2 Kings 6:17).
The Lord is also like an impregnable wall of mountains surrounding His people: "As the mountains are round about Jerusalem, so the LORD is round about his people from henceforth even for ever" (Psalm 125:2). The earthly Jerusalem is a foreshadowing of the new Jerusalem, which will have "a wall great and high" (Revelation 21:12), within which will dwell safely forever all "the nations of them which are saved" (Revelation 21:24).
"In that day shall this song be sung. . . . We have a strong city; salvation will God appoint for walls and bulwarks" (Isaiah 26:1). In type now, in reality in eternity, the great wall of mountains and angels and divine fire is none other than our great salvation in Christ: "Violence shall no more be heard in thy land, wasting nor destruction within thy borders; but thou shalt call thy walls Salvation, and thy gates Praise" (Isaiah 60:18). HMM