The third chapter of the third book in C.S. Lewis's Mere Christianity is on social morality. It explains that "the Golden Rule of the New Testament (Do as you would be done by) is a summing up of what everyone, at bottom, had always known to be right....Christianity has not...a detailed political programme for applying 'Do as you would be done by' to a particular society at a particular moment.... It is meant for all men at all times and the particular programme which suited one place or time would not suit another....It was never intended to replace or supersede the ordinary human arts and sciences: it is rather a director which will set them all to the right jobs, and a source of energy which will give them all new life, if only they will put themselves at its disposal."
"People say, 'The Church ought to give us a lead.' That is true if they mean it in the right way, but false if they mean it in the wrong way. By the church they ought to mean the whole body of practicing Christians. And when they say that the Church should give us a lead, they ought to mean that some Christians—those who happen to have the right talents—should be economists and statesmen, and that all economists and statesmen should be Christians, and that their whole efforts in politics and economics should be directed to putting 'Do as you would be done by' into action. If that happened and if we others were really ready to take it, then we should find the Christian solution for our own social problems pretty quickly. But, of course, when they ask for a lead from the Church most people mean they want the clergy to put out a political program. That is silly. The clergy are those particular people within the whole Church who have been specially trained and set aside to look after what concerns us as creatures who are going to live forever.... The application of Christian principles, say, to trade unionism or education, must come from Christian trade unionists and Christian [educators]: just as Christian literature comes from Christian novelists and dramatists—not from the bench of bishops getting together and trying to write plays and novels in their spare time."
From a biblical view of society, "there are to be no passengers or parasites: if a man does not work, he ought not to eat. Everyone is to work with his own hands, and what is more, everyone's work is to produce something good...no manufacture of silly luxuries and then of sillier advertisements to buy them....To that extent a Christian society would be what we now call Leftist. On the other hand, it is always insisting on obedience ...and...respect...to properly appointed magistrates, from children to parents, and...from wives to husbands. Thirdly, it is to be a cheerful society: full of singing and rejoicing, and regarding worry or anxiety as wrong. Courtesy is one of the Christian virtues; and the New Testament hates what it calls 'busybodies.'"
"In the passage where the New Testament says that everyone must work, it gives as a reason 'in order that he may have something to give to those in need'....I do not believe one can settle how much we ought to give. I am afraid the only safe rule is to give more than we can spare....There ought to be things we should like to do and cannot because our [charitable expenditures exclude] them."
"Christianity is the total plan for the human machine. We have all departed from that total plan in different ways ....Everyone is attracted by bits of it and wants to pick out those bits and leave the rest....A Christian society is not going to arrive until most of us really want it: and we are not going to want it until we become fully Christian. I may repeat 'Do as you would be done by' till I am black in the face, but I cannot really carry it out till I love my neighbor as myself: and I cannot learn to love my neighbor as myself till I learn to love God....We are driven on to something more inward...from social matters to religious matters. For the longest way round is the shortest way home."
Highlights from chapter 3: Social Morality, book 3: Christian Behaviour in Mere Christianity by C.S. Lewis. Click here for a clear view of how this chapter relates to the whole book.