But concerning the times and the seasons, brethren, you have no need that I should write to you. (2) For you yourselves know perfectly that the day of the Lord so comes as a thief in the night. (3) For when they say, “Peace and safety!” then sudden destruction comes upon them, as labor pains upon a pregnant woman. And they shall not escape. (4) But you, brethren, are not in darkness, so that this Day should overtake you as a thief. (5) You are all sons of light and sons of the day. We are not of the night or of darkness. (6) Therefore let us not sleep, as others do, but let us watch and be sober.

The first letter to the Thessalonians was written by the apostle Paul. He has just dealt with the question of what will happen to the faithful on the Day of the Lord – they will be delivered from the coming wrath of God. They will already have been resurrected before the wrath begins. The faithful are “sons of light and sons of the day” and Paul makes a direct contrast between the situation of unbelievers and that of believers.

The concept of the Day of the Lord refers to God’s intervention in history for judgment or for deliverance and blessing of God’s people. The Day of the Lord is certainly coming and will be sudden, unexpected and inescapable for those in spiritual darkness. Our focus should not be on fixing dates but on the spreading of the gospel to those who will face God’s judgment if they do not repent. This Day will come like a thief in the night. We are given a picture that people will be enjoying peace and prosperity and they will not feel the need to get right with God. The destruction will be sudden; there are no alternatives other than life with the Lord or eternal loss – one or the other is inevitable. Believers will not be surprised at the Day of the Lord because we will expect it but unbelievers are oblivious to physical or spiritual danger. Believers should live each day alert and ready for the Lord.

We are living in serious times. As Christians our citizenship is in heaven and the Day of the Lord is for us the day of salvation. The faithful will have no part in the day of wrath; the time of still future fulfillment when God’s wrath is poured out on unbelievers. It will be a time of judgment and a time of salvation. This will be the ultimate fulfillment of prophecy concerning events at the end of history when Gods punishes evil and fulfills all His promises.