What does 1 Thessalonians 5:6 mean?

Paul has been discussing the rapture: a future, abrupt moment when Christ will retrieve believers from the earth (1 Thessalonians 4:16–17). This moment is one the Thessalonians are prepared for, so they won't be caught off guard the way unbelievers will (1 Thessalonians 5:2–3). Paul emphasized this point in the prior verse by referring to these Christians as "children of light, children of the day."

Because the Thessalonian believers had come to know the Light of the world and the truth of the gospel, Paul calls on them to stay alert and self-disciplined. He urges them not to "sleep," appealing to them not to be apathetic or uncaring. Believers need to be alert and self-disciplined as they watch for the Lord's return to take them to heaven.

Paul issues a similar appeal to the Christians at Ephesus. In Ephesians 5:15–16 he writes, "Look carefully then how you walk, not as unwise but as wise, making the best use of the time, because the days are evil." If believers fail to be alert to the times and the hopeless condition of the children of darkness, how will they win the lost to Christ? In Ephesians 6:18 he admonishes believers to "keep alert with all perseverance."

The apostle Peter also appeals for sobriety—meaning self-discipline—and watchfulness. Similarly, Peter writes: "Be sober-minded; be watchful. Your adversary the devil prowls around like a roaring lion, seeking someone to devour" (1 Peter 5:8).