What does Psalm 91:9 mean?

Once again, as in verses 1 and 2, the psalmist refers to God using terms of stability, safety, and consistency. Moving away from that protection and wisdom is a path to disaster (Proverbs 9:11–12).

Israel was supposed to regard God as its supreme King. He had promised to protect the nation, but the people of Israel wanted to be like the other cultures around them. They demanded the prophet Samuel give them an earthly king (1 Samuel 8:5). Their demand displeased Samuel, but the Lord told Samuel to grant their request. He told Samuel: "They have rejected me from being king over them" (1 Samuel 8:7). Israel's choice was a bad one. They preferred an earthly king to the Most High who is far above every earthly king. The Hebrew word used here is el'yon', which means something above or far higher than anything else.

As this psalm points out, God is a safe object of trust for all people. Earthly kings die, but the Most High is an eternal king. When King Uzziah died, Isaiah entered the temple and received a vision of the eternal King, high and lifted up (Isaiah 6). He heard seraphim call out that the Most High God is holy and the whole earth is full of His glory (Isaiah 6:1–3).