What does Psalm 52:4 mean?

Prior verses condemned a man for false valor, violence, and deceit (Psalm 52:1–3). That man is Doeg, an Edomite who betrayed David's allies and murdered innocents on Saul's orders (1 Samuel 22:9–10, 17–19). This verse repeats criticism about Doeg's speech, which led directly to the deaths of priests and their families. Most likely, he chose to betray the priests to ingratiate himself with King Saul.

Evil, damaging words are not always direct attacks. Paul alerted Timothy, a pastor, to the emergence of deceitful false teachers. He writes in 1 Timothy 4:1–2: "Now the Spirit expressly says that in later times some will depart from the faith by devoting themselves to deceitful spirits and teachings of demons, through the insincerity of liars whose consciences are seared." Paul also alerted Titus, another pastor, to the presence of "many who are insubordinate, empty talkers and deceivers" (Titus 1:10). Jesus predicted the presence of false prophets in the end times, He said, "Many will come in my name, saying, 'I am the Christ,' and they will lead many astray" (Matthew 24:5). Jesus performed signs to show that He was the Christ and to lead those who believed to the Father (John 14:6; 20:30–31). In the tribulation the False Prophet will perform signs to persuade unbelievers to worship the Antichrist (Revelation 13:13–14).