A quote from Ralph Winter's book, Frontiers in Mission: Discovering and Surmounting Barriers to the Missio Dei, from page 227:
At this point it is quite possible that some will say, ‘What in the world could microbes have to do with the Kingdom of God or global evangelism?’ The answer is simple. Distorted microbes war against the Kingdom of God. Distorted genes make animals violent and destructive. Destructive parasites kill off many varieties of plant and animal life, and as well as, by the malarial parasite, 1.2 million people a year, most of them children, four of whom die every minute from malaria alone. All this massive damage to the purposes of the Kingdom of God amounts to noise so loud that people can’t hear what we are preaching to them.
