Other Changes
Islam reduced the devastating effect of blood feuds, which was common among Arabs, by encouraging compensation in money rather than blood. In case the aggrieved party insisted on blood, unlike the pre-Islamic Arab tradition in which any male relative could be slain, only the culprit himself could be executed.
The Cambridge History of Islam states that the nomadic structure of pre-Islamic Arabia had the serious moral problem of the care of the poor and the unfortunate. "Not merely did the Qur'an urge men to show care and concern for the needy, but in its teaching about the Last day it asserted the existence of a sanction applicable to men as individuals in matters where their selfishness was no longer restrained by nomadic ideas of dishonour."
Islam teaches support for the poor and the oppressed. In an effort to protect and help the poor and orphans, regular almsgiving — zakat — was made obligatory for Muslims. This regular alms-giving developed into a form of income tax to be used exclusively for welfare.
Read more about this topic: Early Social Changes Under Islam