What does Psalm 52:5 mean?

David expresses confidence that God will punish Doeg and all who are like him. Doeg was a livestock manager who sided with Saul over David (1 Samuel 22:9–10, 17–19). His words and actions led to the brutal deaths of many innocent people. For that, David sarcastically referred to Doeg as a "mighty man" (Psalm 52:1) and condemned him for his evil tongue (Psalm 52:2–4). The expected reaction to this wickedness is death. David fully expects the Lord to put Doeg to death for his crimes, making him an example to others (Psalm 52:6–7).

Acts 12 mentions another man who preferred evil and was ultimately killed in response to his wicked words. King Herod was a proud persecutor of the righteous. He killed James, the brother of John, and apprehended Peter (Acts 12:1–4). He intended to execute Peter as he had James. But God intervened and freed Peter from prison (Acts 12:6–17). Infuriated, Herod ordered the execution of the prison guards who he believed were responsible for Peter's escape (Acts 12:19). Later, Herod donned his royal robes, sat on a throne, and addressed the people of Tyre and Sidon (Acts 12:20–21). When the people proclaimed that he was a god, immediately an angel of the Lord struck him down, and worms consumed him (Acts 12:22–23).