What does Psalm 124:4 mean?

This continues an explanation of what would have happened to Israel if the Lord had not been on their side (Psalm 124:1–4). It was made clear that only God's power kept the nation from being defeated and erased from the world. Many examples in Israel's history demonstrate this to be true (Exodus 12:14; Deuteronomy 4:37–38; 2 Samuel 10:6; 2 Kings 19:32–36). Even when God allowed them to be captured (2 Chronicles 36:17–21), the Lord's power kept them alive and restored them to the land (Ezra 2:1).

Now the psalmist compares these enemies to a flood. This is a common symbol used to imply overwhelming power. The most obvious effect of a flood is how it completely surrounds and overpowers an entire area. The strength of moving water can be catastrophic. When enemies are compared to a flood, there is no possible way for the victim to withstand the assault. That Israel has survived is proof that God was acting on their behalf.

Floods have appeared in Scripture to demonstrate the Lord's power and the universal effect of His judgment. A flood was used to destroy the wicked world in the days of Noah (Genesis 7:17–23). When Israel left Egypt (Exodus 12:41), God allowed the Israelites to cross the Red Sea on dry land and wiped out the pursuing Egyptian army with those same waters (Exodus 14:28; 15:4–5).