What does Psalm 52:2 mean?

Doeg the Edomite informed David's enemy Saul about David's encounter with the priest Ahimelech (1 Samuel 22:9–10). He then slaughtered those priests and countless innocents at Saul's command (1 Samuel 22:17–19). For this, David sarcastically calls him a "mighty man" and condemns him for arrogance (Psalm 52:1).

Those killed by Doeg were ultimately done in by his words. Doeg saw David with the priest, and he chose to pass that information to the unstable, murderous King Saul. Little is recorded about that event (1 Samuel 21:1–9), but this verse implies Doeg was dishonest in his account. Perhaps he exaggerated the support given by the priest. Or, he might have withheld information to make himself look more heroic for informing. Either way, his words led to horrific violence against innocent people. His tongue acts like a razor, slashing those against whom he speaks (Psalm 57:4).

In Psalm 55:21, David describes the deceitful nature of an enemy's speech: "smooth as butter," although "war was in his heart; his words were softer than oil, yet they were drawn swords." The apostle Paul warned the churches of Galatia about deceitful men like Doeg. They flattered the Galatian believers to win them to their side, away from the truth. He asks in Galatians 3:1, "O foolish Galatians! Who has bewitched you?" He accuses the false teachers, in Galatians 4:17, of making much of the Galatians, "but for no good purpose. They want to shut you out, that you may make much of them."