The Sermon on the Mount is probably the best-known part of the teaching of Jesus, though arguably it is the least understood, and certainly it is the least obeyed. It is the nearest thing to a manifesto that he ever uttered, for it is his own description of what he wanted his followers to be and to do. To my mind no two words sum up its intention better, or indicate more clearly its challenge to the modern world, than the expression ‘Christian counter-culture’.