Surah al-A`raf (The Elevated Places) 7 : 165

Explanatory Note

Thus, the inhabitants of that city were divided into three groups, or three communities. In Islamic terminology, a nation or a community is a group of people who believe in one faith, have the same concept, and admit allegiance to a single leadership. It is thus different from the definitions given to it in non-Muslim societies, ancient and modern, which make a nation any group of people living in a particular area and governed by a particular regime. This concept is alien to Islam.
 
Hence, we say that the inhabitants of that city were divided into three groups: a clearly disobedient one, and one opposed to the sly schemes of disobedience to God, taking a positive action or denouncing disobedience and giving admonition. A third group adopted a negative attitude, disapproving of those disobedient schemes but taking no positive action to repel them. Each group had its own concept and line of action, which made each of them a separate nation. When warnings and admonition were apparently useless, and the disobedient group persisted with their erring ways, God’s warnings had to be fulfilled. Those who admonished them were saved, while the disobedient community suffered a very severe punishment, as will be explained presently. The sūrah does not mention what happened to the third group or community, perhaps in order to indicate that they were of no consequence, because they refrained from taking positive action and were satisfied to disapprove of God’s disobedience only in a negative way. Hence, they deserved to be ignored although they did not incur punishment.