Robbery and murder were also of common occurrence; human blood being almost daily shed without remorse or horror.
Structurally, tribal groups are defined by common patrilineal descent. This lineage is the unit that shares joint responsibility for avenging the wrongs its members may suffer and, conversely, paying compensation to anyone whom its members have aggrieved. Although tribes may differ in their status, all lineages of a given tribe are considered equal. However, social stratification was linked to this population diversity. Tribal affiliation constituted a major status category based on bloodline. At the top of the tribal status category were the qabila, families that could claim purity. Qabila families considered themselves distinct from and distinctly superior to non tribal families, who could not claim qabila descent. Non tribal families include most tradesmen, artisans, merchants, and scholars, and constituted the bulk of the urban productive population of pre-oil Arabia. Marriage between individuals of qabila and non tribal status was not normally considered. The claim to qabila status was maintained by patrilineal descent; therefore, qabila families were concerned to observe strict rules of endogamy (marriage back into the paternal line) so that status might be maintained and children, who were considered to belong to the family of the father. Within the qabila status group, however, there were status differentials, some groups being considered inferior precisely because they had once intermarried from outside the qabila thus unable to claim purity of descent. .
In pre Islamic period, there were two trading months that were known in the desert of the Arab Peninsula as the two "forbidden months". Arab tribes and individuals were forbidden to launch ghazzu raids and attacks during these two trading months. The tradition was respected throughout the whole Peninsula, mainly for safety of the travelers and trade and survival of the Arab desert's economy.
