The previous verses contained Paul’s explanation concerning that of which the Thessalonians were ignorant (cf. 4:13-18). The current text serves as a reminder of things of which the brethren were already informed – the coming of the Day of the Lord, and the conduct to be assumed by those who look forward to that day.

When is the Day of the Lord going to take place? This is that which Paul had no need to write about. For the Thessalonians had already been informed. They were not given a specific time, or specific signs that would immediately precede that Day, but information concerning the nature of its coming. “As a thief in the night” (v. 2) would the Day of the Lord come. It will consist of no warning (save that of the text, and the rest of scripture), and no time frame. For those unaware, who sit in complacency, the destruction will be “sudden.”

The Christian, however, is not to be taken by surprise like the victim of thievery, or the woman experiencing sudden birth. The Christian is a child of God, and as such, a child of light (cf. 1 John 1:5-7; Ephesians 5:8-14). Enlightened by the participant knowledge of God’s word (cf. 1 John 2:3-6; Hebrews 6:4), Christians are those who are taken from darkness, and put into the light (cf. Colossians 1:13). They have no excuse for unpreparedness. Therefore, instead of stooping to a moral slumber and inebriation, the child of light and day should be ready for the coming of that Day by guarding himself with active love and faith. Comfort comes with the fact that the child of God is given the hope of salvation. That Day will be terrible for most, but wonderful for the Christian. Living with the hope of this salvation ensures focus, and preparedness. Each of us is charged with the responsibility to consistently comfort and edify one another with these facts (v. 11).