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In 1 Thessalonians 5:2 Paul writes, “For you yourselves are fully aware that the day of the Lord will come like a thief in the night.” What does this mean?
The previous context helps answer this question. Verse 1 notes, “Now concerning the times and the seasons, brothers, you have no need to have anything written to you.” Paul had just noted that his readers did not need information about the exact time or season Jesus would return. Instead, Jesus would return at any moment, unexpectedly like a thief in the night.
The analogy of a thief in the night was a common one in Paul’s culture. A thief did not generally operate in the daytime since he could be seen. Instead, he would commit his crime in the cover of darkness where his identity could be concealed. During a time when a home was empty, he could enter and remove items without being detected. Even when a person was home, a thief could quietly enter and commit a crime without being seen.
In contrast, Paul commanded his readers, “So then let us not sleep, as others do, but let us keep awake and be sober” (1 Thessalonians 5:6). Paul offered three commands in his response. First, we are not to sleep. This means we must be prepared for Christ’s coming, both in believing in Him (as the Thessalonian believers already had) and by living a godly life.
Second, Paul commanded us to keep awake. This is the opposite of sleeping. We are not to simply keep one eye open spiritually, but be fully awake, completely committed to serving Christ.
Third, we are to be sober. In other words, we are to make efforts to stay healthy and fully alert in our walk with God. We are not to serve God with apathy or half-hearted efforts, but rather serve Him passionately.
Finally, Paul concludes his teaching in this section by saying, “Therefore encourage one another and build one another up, just as you are doing” (1 Thessalonians 5:11). These believers were already encouraging and helping one another. Paul instructed them to continue these practices. Their example is fitting for our lives as well. We can better serve the Lord “awake and sober” when we encourage other believers, build them up, and are likewise encouraged by them. The Christian life is not intended as a solo effort, but is rather a team sport.
Jesus will return at any moment, like a thief in the night. This should motivate every believer to a life of devotion, service, and encouragement to other believers as we look forward to this day.
https://www.compellingtruth.org/thief-in-the-night.html