Detail an example of social mobility in muslim society in the eighth and ninth cetnuries

The social stratification of Muslims was not so rigid in early medieval period. The Quran  repeatedly advocates the concept of an egalitarian society. The social mobility of Muslims in early medieval period was one of the reasons which helped Muslims to establish their empires allover the world and spread the teachings of Islam.

One example of social mobility in Muslim society  in the eighth and early ninth centuries was that the slaves- the bottom class of society could rose to higher ranks in administration. We see during this period there were so many slaves who were great military generals and ministers. They rose to the position of governors of provinces as well. It were the khurasan slaves who helped the Abassids to establish such a great empire. The Muslim rulers even married their daughters to these slaves who later became the emperor of Muslim kingdoms as well.