Verse 4
Glad and sing for joy - They shall be made happy in thy salvation. Even their political state shall be greatly meliorated; for God will be acknowledged the supreme Judge; their laws shall be founded on his word; and the nations of the earth shall be governed according to judgment, justice, and equity.
Selah - This is true. There are innumerable facts to confirm it. All the nations who have received the Gospel of Christ have been benefited politically, as well as spiritually, by it.