CS Lewis

His teaching on the subject quite clearly consisted of three propositions. One, that He will certainly return. Two, that we cannot possibly find out when. Three, and that therefore we must always be ready for Him. Note the therefore. Only because we cannot predict the moment, we must be ready at all moments. Our Lord repeated this practical conclusion again and again, as if the promise of the return had been made for the sake of this conclusion alone.

Watch, watch, is the burden of His advice. I shall come like a thief. You will not, I most solemnly assure you, you will not see Me approaching. If the householder had known at what time the burglar would arrive, he would have been ready for him. If the servant had known when his absent employer would come home, he would not have been found drunk in the kitchen. But they didn’t, nor will you. Therefore you must be ready at all times.

The point is surely simple enough. The schoolboy does not know which part of his Virgil lesson he will be made to translate. That is why he must be prepared to translate any passage. The sentry does not know at what time an enemy will attack, or an officer inspect his post. That is why he must keep awake all the time.

The return is wholly unpredictable. There will be wars and rumors of wars, and all kinds of catastrophes, as there always are. Things will be, in that sense, normal, the hour before the heavens roll up like a scroll. You cannot guess it. If you could, one chief purpose for which it was foretold would be frustrated. And God’s purposes are not so easily frustrated as that. One’s ears should be closed against any future William Miller in advance. The folly of listening to him at all is almost equal to the folly of believing him. He couldn’t know what he pretends, or thinks he knows.

Of this folly George MacDonald has written well. Do those, he asks, who say, lo here or lo there are the signs of his coming, think to be too keen for him, and spy his approach? When he tells them to watch, lest he find them neglecting their work, they stare this way and that, and watch lest he should succeed in coming like a thief. Obedience is the one key of life.

The doctrine of the second coming has failed, so far as we are concerned, if it does not make us realize that at every moment of every day in our lives Don’s question, ‘What if this present were the world’s last night?’...

What is important is not that we should always fear or hope about the end, but that we should always remember, always take it into account. An analogy may help here. A man of seventy need not be always feeling, much less talking, about his approaching death. But a wise man of seventy should always take it into account.