What does Psalm 17:12 mean?

Concerned about danger in the prior verse, David shifted from speaking about himself (Psalm 17:8–9) to speaking of a group (Psalm 17:11). These were probably the men who fought beside him (1 Samuel 22:1–2) when he was persecuted by Saul (1 Samuel 20:32–33). In another shift, David changes from speaking of his enemies—plural (Psalm 17:9–10)—to a single person, saying "he" is a threat. Most likely, this person is Saul.

David compares Saul to a ferocious lion eager to surprise prey and rip its victim apart. Saul was certainly bloodthirsty and eager to ambush David and kill him. When David served in Saul's court, Saul demonstrated his savage side. At least twice he threw his spear at David, hoping to pin David to the wall (1 Samuel 18:11; 19:10). He sent soldiers four times to capture David (1 Samuel 19:11–23). Finally, he personally led the search for David in the wilderness (1 Samuel 23:24–25).

Today, believers face a ferocious enemy: Satan. The apostle Peter depicts him as a roaring lion that prowls around in search of someone to devour (1 Peter 5:8). The way to escape is to be sober-minded, watchful, and strong in the faith (1 Peter 5:8–9).