The people who came home from Babylon had experienced a wonderful redemption, But believers in Jesus Christ have been redeemed in a far more wonderful way.
The first commandment tells that we must worship God alone. The second tells us that we must worship God as he really is.
The folk who first sang this Psalm looked back on the past. But as they did so, they were driven to pray for the future.
The God of the Bible will accept no rivals. He demands all of our worship, all our obedience, all our love.
The story of the Israelites who left Egypt was a story of repeated sin and failure but where sin abounded, grace abounded all the more.