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 nor of darkness.  (6) Therefore let us not sleep, as others do, but let us watch and be sober.

The Apostle Paul wrote the first letter to the Thessalonians in response to questions the Christian faithful had about the timing and events of the second coming of Christ Jesus.  Paul has just finished writing about the rapture (a non-biblical term) when the justified faithful will be gathered by Christ.  Then follows the Day of the Lord when the unwelcome terrible judgment of the Lord will judge sinful, unrepentant man.  Paul is telling the faithful that they do not need to know the time of the day of the Lord or the coming wrath of God as they will not be present on that day.   Further, they not only do not need to know the time, they cannot know it.

The Day of the Lord – the day of end time and judgment for the ungodly, the day of darkness, will not overtake the faithful because we are not people of the night.  We are day people, people of the Light.  We have experienced the transforming power of the gospel.  We are reborn but still of a fallen nature so Paul is warning the Thessalonians – and us – to not fall asleep to spiritual reality.  We have been redeemed out of darkness and as day people we are to act like it.  This is now our nature, our destiny.

The Day of the Lord is coming and it will be quick and terrible.  There will be signs but the children of the night, living in mental and moral darkness  will still not believe it.  They will be saying peace and safety, everything will be just fine, when, like a thief in the night, the end times will be upon them.

The faithful are not living in darkness and should live holy lives.  Through a series of contrasts Paul addresses the future of the believers:  dark and light, sober and drunk, asleep and awake, day and night, being separated from God forever and being with God forever.  There is total division between believers and non-believers – the saved and the damned.  So the Day of the Lord, the day of wrath is coming – but not for the believer.