The man of sin (Greek: ὁ ἄνθρωπος τῆς ἁμαρτίας, ho anthrōpos tēs hamartias) or man of lawlessness (ἀνομίας, anomias), man of rebellion, man of insurrection, or man of apostasy is a figure referred to in the Christian Bible in the Second Epistle to the Thessalonians. He is usually equated with the Antichrist in Christian eschatology.
In Christian eschatology, Antichrist, or in broader eschatology, Anti-Messiah, refers to a kind of entity prophesied by the Bible to oppose Jesus Christ and falsely substitute himself as a savior in Christ's place before the Second Coming. The term Antichrist (including one plural form) is found four times in the New Testament, solely in the First and Second Epistle of John. Antichrist is announced as one "who denies the Father and the Son."
The similar term pseudokhristos or "false Christ" is also found in the Gospels. In Matthew (chapter 24) and Mark (chapter 13), Jesus alerts his disciples not to be deceived by the false prophets, who will claim themselves to be the Christ, performing "great signs and wonders". Three other images often associated with Antichrist are the "little horn" in Daniel's final vision, the "man of sin" in Paul the Apostle's Second Epistle to the Thessalonians, and the Beast of the Sea in the Book of Revelation.