In 1 Thessalonians 5, Paul writes about how "the day of the Lord will come like a thief in the night". Here, Paul uses the phrase "day of the Lord" to refer to the return of Christ. However, it is worth nothing that this is not a phrase Paul simply made up. It is one used regularly in the Old Testament (see Isaiah 13:6, Ezekiel 13:5, Joel 1:15, 2:1, 2:31, 4:14, Amos 5:18, Zephaniah 1:14, Obadiah 15, Malachi 3:1-2) to speak of a day of judgement and God's justice being fulfilled. The coming of the Lord is often pronounced as a fearful message for those who have opposed God but it is a hopeful one for those who have heeded his commands. This is the case because the day of the Lord means the establishment of God's reign and righteousness which in turn means the defense of the needy and the casting out of the oppressor. Paul believes that all the promises/curses associated with the day of the Lord will be fulfilled by Jesus when establishes God's kingdom in its fullness.
I mentioned briefly last week that Paul's description of the day of the Lord being like a thief in the night does not mean that it will be secret, it will not come and go stealthily unnoticed. Paul's words in 1 Thessalonians 4:16, as well as the descriptions of this day by the prophets, make it very clear that it will be an obvious and publicly observable event. Instead, this metaphor speaks to its suddenness and unexpectedness and its demand for constant watchfulness. One never knows when a thief might try to break in. Additionally, while we might take reasonable precautions to keep thieves out (locks, gates, alarm systems, etc) any of those precautions might be defeated by a thief that is determined enough. There is no advance preparation that can be guaranteed to keep out the thief and provide complete safety and invulnerability. The only fail safe is to keep constant vigil. Paul says the day of the Lord is like this; there is no time for sleeping or drunkenness, no time in which we can rest on the merits of what we have already done. The Christian life demands continual watchfulness; a constant seeking after God.
Paul continues to strike at this illusion of security in 5:3 when he says "While people are saying "There is peace and security then sudden destruction will come upon them as labor pains come upon a pregnant woman...". Commentators on this verse will point out that other historical documents of the period suggest that "peace and security" was sort of a slogan of the Roman Empire. It was Caesar and his empire who had provided peace and security for the world. Paul, then, seems to be undercutting not only the Thessalonians individual attempts to provide peace and security for themselves but also their attempt to do so by finding their identity with the Roman narrative. Paul is challenging them to trust in a crucified messiah rather than placing their trust in a vast empire that had spanned the known world and promised to provide everything for everyone.
Such a challenge is ripe with implications for the Church in America. The world has never seen a group of Christians as comfortable as we are, who have enjoyed as much peace and security as we have. The problem with being comfortable is that it makes it very easy to fall asleep, very difficult to remain watchful. What is worse is that most of us have bought into the narrative that it is our nation that has provided these things for us. Paul calls us to a different narrative; a story where we find our peace and security in God alone, even when that peace and security may not provide comfort, and to keep watch, constantly being vigilant for the Spirit's leading.