What does 'the departure' mean in 2 Thessalonians 2:3?
In 2 Thessalonians 2:3, 'the departure' means the removal of believers from this place to the other—a sudden departure—that must occur before the man of sin is revealed and the tribulation begins. The tribulation cannot begin until this departure happens.
Les explains that the term can mean either a person departing from another person or a person departing from one place to another. In this text, he says that distinction makes all the difference: the tribulation cannot begin until there is the departure. He applies this to believers, saying 'you and I' will depart—suddenly gone from this place to the other. Only then is the man of sin, the son of perdition, revealed. Les also notes that Judas Iscariot was called the son of perdition and went to his own place, while Revelation speaks of the Antichrist as the son of perdition who came from his own place, suggesting possible Scriptural analogies.