Be Alert. 1st Thessalonians 5:4 This is the second time in this chapter that Paul uses the word “brethren” to distinguish between those who say “Peace and safety” and those who are truly at peace with God and safe in Christ as they face Judgment. Darkness represents sinfulness, while light signifies godliness. The day of the Lord will catch those in darkness unprepared but will not catch Christians because they anticipate that day and are ready for it at any moment.
Christians are aware of this fact and should not be surprised that it will happen. The return of the Lord will be sudden; even though we don't know when it will occur, we will have no time to make quick adjustments. We should conduct ourselves daily as if it will happen today. As children of light, the new birth has given us the ability to understand God's word. This is not reflected light from others but direct light from God, part of our new nature. By not knowing the exact date of His return, we will continue with our work here and avoid anything we know is wrong until we die or the Lord comes. We do not belong in darkness, nor are we in the condition of the unsaved.
Even though believers lived in darkness before they became Christians, they no longer do and do not belong there. Our righteousness in living before the scrutiny of those in the world and godliness in character that reflects our Lord Jesus Christ are evidence of who we are, despite what is going on around us. Christians should stand out as different in attitude, actions, faith, and moral character. The fact that Christ is coming at any time motivates them to live for Him.