We find this imperative in the book of Mark, in a section in which Jesus talks about the end times. The immediate context of this verses is:
Mark 13: 32 “But about that day or hour no one knows, not even the angels in heaven, nor the Son, but only the Father. 33 Be on guard! Be alert! You do not know when that time will come. 34 It’s like a man going away: He leaves his house and puts his servants in charge, each with their assigned task, and tells the one at the door to keep watch. 35 “Therefore keep watch because you do not know when the owner of the house will come back—whether in the evening, or at midnight, or when the rooster crows, or at dawn. 36 If he comes suddenly, do not let him find you sleeping. 37 What I say to you, I say to everyone: ‘Watch!’”
Frequently, when Jesus talks about Himself and His second coming, he uses the analogy of a Lord or King who is going away and is coming back (Matthew 13, 20, 24, 25, Mark 12, 13, and Luke 12, 17, 19, 20). Before his departure, he gives tasks to the servants, and when he comes back, he will require an account of how they have executed their tasks.
The servants have the honorable charge to take care of the house in the absence of their Lord. If they do their jobs well, the Lord will tell them “Well done, good and faithful steward” and He will reward them according to their works. If they don’t do their job, He will tell them “You wicked and lazy servant” and their reward will be taken from them. And if, instead of doing their job, they are doing evil and abuse other servants, they will be punished (Luke 12:45). In this parable, the emphasis is placed on the uncertainty of the timing of His return, and the requirement therefore for the servants to be on their guard.
The timing of the return of Christ has been a point of discussion ever since He left. The Bible gives some clues about this timing, but even Jesus did not know it (verse 32). Regardless of when it will actually happen, Christians (the servants) need to be always on their guard. We want to be found awake, doing the Lord’s will, always. Even if Christ does not come back for another 2000 years, we could be hit by a bus today.
As servants, we should know what our Lord wants us to do, and then do it. It’s hard to please your boss if you don’t know what he or she wants. But how do we know what our Lord wants? By listening very carefully to His instructions. This is why it’s so important to read God’s Word daily. In His Word, God gives us direct commands, general principles, and examples of people who pleased or displeased Him. This is how we know what is expected of us, which tasks the Lord has assigned to us. Make sure you are doing them when He comes back and do not let him find you sleeping!