There’s an old cliche that goes like this: “They’re so heavenly minded they’re no earthly good.” It’s a criticism of religious folks who are all talk, but don’t seem to do much. Perhaps they turn a blind eye to the needs of the world around them. Perhaps they’ve grown cynical about the here and now–and have couched that cynicism in religious language about future “streets of gold” and the “crystal sea.”

But the antidote to escapism is not to think of heaven less–but to think of it better. True heavenly mindedness does not demotivate courageous action, but spurs it on. Why not sacrificially give your time, your service, your wealth, your very life for others? If you’re a believer, you’ve got nothing to lose.

If you read history you will find that the Christians who did the most for the present world were just those who thought most of the next. The Apostles themselves, who set on foot the conversion of the Roman Empire, the great men who built up the Middle Ages, the English Evangelicals who abolished the Slave Trade, all left their mark on Earth, precisely because their minds were occupied with Heaven. It is since Christians have largely ceased to think of the other world that they have become so ineffective in this. Aim at Heaven and you will get earth ‘thrown in’; aim at earth and you will get neither.

C.S. Lewis, Mere Christianity, bk 3, ch. 10.