What does Psalm 56:7 mean?

The first part of this verse is "rhetorical:" phrased like a question yet making a firm statement. David dismisses the idea that those who attack him will avoid God's judgment. The forces of Saul were seeking to kill him (1 Samuel 19:1–2, 18; 20:1–42), so David fled into enemy territory (Psalm 56:1; 1 Samuel 21:10). There, he was recognized by the Philistines and so pretended to be insane to confuse them (1 Samuel 21:11–15). With his trust in the Lord's goodness (Psalm 56:4), David confidently calls on God to strike down these lurking evildoers (Psalm 56:6).

Modern religious culture is often uncomfortable with the concept of God's wrath. The preferred emphasis is on His love, with the result being that many assume the Lord is "too loving" to judge anyone. This ignores the fact that God is also just, and holy, and perfect (Psalm 29:2; 145:17). He abhors sin and judges the unrepentant sinner. John 3:16 describes God's love as so astounding that He gave His only Son, saving those who trust Him for salvation. However, John 3:36 warns that whoever rejects God's Son lives under the wrath of God. In the tribulation the wrath of God's Son, the Lamb, will be poured out, and the question is asked: "Who can stand?" (Revelation 6:17). The final display of God's wrath awaits the Great White Throne Judgment, when all unbelievers will be cast into the lake of fire (Revelation 20:11–15).