What does 'except the Lord keep the city' mean for Christians today?

The phrase 'except the Lord keep the city' serves as a profound reminder of the futility of our human efforts in securing safety without divine intervention. It highlights the reality that, as Christians, we are entirely reliant on God’s sovereignty to protect not only our physical spaces but also our spiritual well-being. The watchman's alertness is useless without God's protection, which applies to all aspects of life today. This principle underscores our call to entrust our lives and circumstances to God, knowing that He is our guardian and sustainer, as expressed in Psalm 121, which affirms that the Lord is our keeper and will preserve us from all evil.