From "The World's Last Night" by C. S. Lewis
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 rung down at any moment: say, before you have finished reading this paragraph. 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 One or Act Five. We do not know who are the major and who the minor characters. The author knows. The audience, if there is an audience (if angels and archangels and all the company of heaven fill the pit and the stalls) may have an inkling. But we, never seeing the play from outside, never meeting any characters except the tiny minority who are "on" in the same scenes as ourselves, wholly ignorant of the future and very imperfectly informed about the past, cannot tell at what moment the end ought to come. That it will come when it ought, we may be sure; but we waste our time in guessing when that will be. That it has a meaning we may be sure, but we cannot see it. When it is over, we may be told. We are led to expect that the Author will have something to say to each of us on the part that each of us has played. The playing it well is what matters infinitely.
The doctrine of the Second Coming has failed, so far as we are concerned, if it does not make us realise that at every moment of every year in our lives Donne's question "What if this present were the world's last night?" is equally relevant.