"Morality (from the Latin moralitas "manner, character, proper behavior") is the differentiation of intentions, decisions, and actions between those that are "good" (or right) and those that are "bad" (or wrong)." WikipediaIf morality is a force, then what is that force?
Living together in groups enhanced our chances of survival and cooperation evolved common codes of conduct we now call moral behavior. Help people and they are likely to help you in return and you all survive, kill people and you are likely to get killed yourself. So people who helped each other survived and over time our brains got more or less hardwired for moral behavior. We know that areas of the brain such as the amygdala are responsible for people being able to distinguish between right and wrong. For those who have damage in those areas or are less "hardwired for morality" some religions explain to these people the difference between right and wrong (The Ten Commandments for example). Obviously naturally moral people don't need to be told.