According to Durkheim, moral codes are indicators of social solidarity because society existed as a moral community above the individuals. Moral codes were codes of conduct that were collectively agreed upon. They reflected the prevailing social conditions and were manifested in the practices in everyday life. The ties that the individuals were bounded with, were important for the society, and these exerted a pressure on people to confirm that the norms and values of the society are not violated by any means.
Therefore, the individual’s behaviour was limited and predictable which made it easy to understand the social solidarity which governed them. For example, caste system in India is a moral code that is reflective of social solidarity among various groups belonging to same caste.