“But about that day or hour no one knows, not even the angels in heaven, nor the Son, but only the Father. Be on guard! Be alert! You do not know when that time will come. 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.
“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. If he comes suddenly, do not let him find you sleeping. What I say to you, I say to everyone: ‘Watch!’”
- Mark 13:32-37
CS Lewis once wrote an essay on the end things. It was called ‘The World’s Last Night’. Here is a flavour.
The doctrine of the Second Coming teaches us that we do not and cannot know when the world drama will end. The curtain may be wrung down at any moment—say, before you have finished reading this paragraph.
[Christian apocalyptic does] not even foretell, which would be more tolerable to our habits of thought, a gradual decay. It foretells a sudden violent end imposed from without. An extinguisher popped on to the candle, a brick flung at the gramophone, a curtain rung down on the play. HALT.
… This seems to some people intolerably frustrating. So many things would be interrupted. Perhaps you were going to get married next month. Perhaps you were going to get a raise next week. You may be on the verge of a great scientific discovery. You may be maturing great social and political reforms. Surely no good and wise God would be so very unreasonable as to cut all this short. Not now—of all moments.
But we think thus because we keep on assuming that we know the play. We do not know the play. We do not even know whether we are in Act I or Act V. We do not know who are the major and who are the minor characters. The author knows.
There are those who think very little about this part of Christian belief. Why? Probably because some think about it far too much, or at least think about it in the wrong way. They're full of passionate conviction that this is the time, these are the signs, and so on.
We need to resist both extremes. Without the prospect of Jesus' return, we're thinking of a King who never brings justice and judgement, a king who allows evil to grow for ever. If we're constantly trying to predict the moment of his return, then we're going straight up against Jesus' own teaching: only the Father knows the hour. Worse than that, we might lose sight of the fact that the servants are left with their assigned tasks - things like love your neighbours and your enemies, preaching the gospel, and so on.
Advent is a time to remember that, "This same Jesus, who has been taken from you into heaven, will come back in the same way you have seen Him go into heaven". We should watch and wait, but also do the things that the Master has asked of us.