They are three words that changed the course of history. In the summer of 1940, Adolf Hitler was desperate to quickly subdue Britain and so be free to turn on his main goal – Russia. The British army had only just escaped at Dunkirk – and without its equipment. England was a sitting duck for invasion, and all Germany needed was control of the skies. Since the Luftwaffe greatly outnumbered the Royal Air Force in planes and especially in experienced pilots, this was not expected to take long.

Instead, it lasted nearly four months and was a decisive British victory. England lived to fight another day. Germany invaded Russia anyhow, and in the end could not sustain the war on two fronts. History looks back on the Battle of Britain as a key turning point. So how was the battle won?

Britain had a secret weapon – radar. It showed them when, where, and in what force the Luftwaffe raids were coming, well before they arrived. Efficient communications systems enabled the RAF planes to be in place and ready for them.

But here’s the remarkable thing: German scientists had also developed radar. What’s more, theirs was more advanced than the rudimentary British system! But here’s the critical difference: The British system was in the field, and the German system was still being perfected in the lab. Sir Robert Watson-Watt, leader of the British research team, used “Second Best Tomorrow” as a motto against perfectionism. Better a basic system in the field tomorrow than the perfect system next year (or the year after).

I wonder whether we could draw on that motto in evangelism and church planting. It’s tempting to plant the perfect church in our imagination. Or to hold off evangelism while we work out the perfect approach that no-one could possibly reject. Such great ministries are developing wonderfully on paper, right when they’re needed in the field! (In fact, that’s where they are far more likely to be truly perfected.)

The simplest of all Jesus’ parables is about two sons who were sent by their father to work in the field. One refused, but then changed his mind and went. His brother had all the right words in response, but never got around to going. Which one, Jesus asked, got it done?