Thieves send no warning messages ahead of them that they are coming, so break-ins are usually sudden and shocking events. We are assured that Christ's return will be equally surprising to most on the earth. The Bible's indications are that He will come when a majority of people least expect Him: when newscasts assure us of "Peace at last!" and the whole world is busy with the affairs of this life (Matthew 24:37-39). Then, everything will fall to pieces with a bang!
Yet, Christians should not be taken by surprise. We are supposed to be aware of the signs of the times, evaluating the course of events, and growing in the grace and knowledge of God, so that, no matter when He comes, we are prepared to meet Christ in the air. Because we are not in darkness, our eyes should be fixed on what is truly important during these troubled times: God's Kingdom and His righteousness.
Like his Master, Paul tells us to watch, and he adds, "Be sober" (verse 6). A sober person's mind is unadulterated by anything that would cause poor judgment, as a drunk's ability to make proper decisions is affected by the booze in his system. One who is sober is serious, thoughtful, cautious, calm, and not given to excesses of any kind. He weighs matters carefully and chooses the wisest course of action.
This should be our stance now, despite what people claim about the timing of Christ's return. The promise of His coming has not been delayed, and things are not as they always were. God's plan marches on; He is maneuvering events, circumstances, and individuals into place. We have been given front-row seats to witness the most astounding series of prophetic fulfillments in human history, and to keep them, we must watch, be sober, and prepare for the return of Jesus Christ.