Stated positively in Matthew and Luke — do to others what you would have them do to you — where Hillel and Confucius and several others state the same idea negatively, as a restraint. The difference is not decorative: a negative rule is satisfied by doing nothing, and a positive one never is. Its weakness is well known and was pointed out from inside the tradition long before Shaw made the joke: it assumes your preferences are a reliable guide to another person's, and it gives no method when two people's legitimate interests actually conflict. Christian ethics has generally treated it as a summary rather than a decision procedure, and put the actual work on the second great commandment and on the specific demands of Matthew 25.