Sabra and Shatila massacre
Civilians are divided, mostly directly because of the organization of the Lebanese society: The society is divided between religious groups. That means if you were a Christian, you were assimilated in the society as a Christian and nothing else. Certain religious groups had certain political rights and occupied specific functions that could not be taken by a member of another group. Christian group was essentially monopolizing the political life while certain Muslim groups, such as  Sunni and Shi'i, were put aside.