"In that day shall this song be sung in the land of Judah; We have a strong city; salvation will God appoint for walls and bulwarks. Open ye the gates, that the righteous nation which keepeth the truth may enter in. Thou wilt keep him in perfect peace, whose mind is stayed on thee: because he trusteth in thee. Trust ye in the LORD for ever: for in the LORD JEHOVAH is everlasting strength:"
In the day of Israel's redemption, a new song of praise will be sung in the kingdom. All four verses comprise this song. Jerusalem will no longer be subject to the enemy's jurisdiction; instead, Jesus Christ will be her center of government. Psalm 48 and 118 parallel the theme of this passage.
The Lord invites every God-fearing nation to enter into Jerusalem for the purpose of worship. Whether Jew or Gentile, it makes no difference. Peter said, "Of a truth I perceive that God is no respecter of persons: But in every nation he that feareth him, and worketh righteousness, is accepted with him (Acts 10:34-35)." Zechariah also predicted many nations coming to millennial Jerusalem for the purpose of praise (Zechariah 14:16).
Verses three and four are well known and may be considered a condensed version of the gospel. Secure is the individual who turns from disbelief to complete faith in the promises of God. Faith in Jesus brings peace of mind. In Ephesians 6:17, salvation's assurance is presented as the helmet which protects the mind from fear and doubt.
The title of LORD JEHOVAH is the same Hebrew name used for God in 12:2. The high and holy name of hwhy hy occupies the verses of both kingdom songs. In JEHOVAH is strength not simply for today or for tomorrow but for eternity. The Lord Jesus is a rock and fortress that will not fail. Faith in His Person will bring the afflicted soul into everlasting peace and strength.