What does Psalm 121:6 mean?

In Israel's hot climate it is possible to experience sunstroke. Also, after the sun sets and night comes, the temperature often drops considerably. Camping out in the cold might cause travelers to become ill. However, in this verse the travelers express their confidence that God would not allow them to experience ill effects from the daytime or the nighttime because of the Lord's watchful care. This confidence is partly literal; these "songs of ascent" were used by pilgrims traveling to Jerusalem for feasts. That often required staying overnight along the roadways (Psalm 121:1–2).

This reference is also symbolic of how God still watches over His people. He cares for us day and night. Psalm 91:1 promises: "He who dwells in the shelter of the Most High will abide in the shadow of the Almighty." Jesus assured His followers there was no need to worry because our heavenly Father provides for us (Matthew 6:25–33).

First Peter 5:7 assures us that He cares for us, and Philippians 4:19 says He will supply every need we have "according to his riches in glory in Christ Jesus." God can, and will, allow believers to experience earthly dangers and harms, at times (John 16:33; Psalm 25:16). However, we can also be unaware of the many times our heavenly Father protects us from danger or provides for us when we have a physical, mental, emotional, or spiritual need. Our response should be to thank God for His daily protection and provision (Romans 8:37–39; 1 Thessalonians 5:16–18; Philippians 4:4-8).