Al-Asqalani used two ayahs from the Qur'an to justify this: Islamic lawyers commented that when the rulers refuse to step down after being impeached through the Majlis, becoming dictators through the support of a corrupt army, if the majority is in agreement they have the option to launch a revolution. Many noted that this option is to be exercised only after factoring in the potential cost of life. Rule of law The following hadith establishes the principle of rule of law in relation to nepotism and accountability Various Islamic lawyers, however, place multiple conditions and stipulations on the execution of such a law, making it difficult to implement. For example, the poor cannot be penalised for stealing out of poverty, and during a time of drought in the Rashidun caliphate, capital punishment was suspended until the effects of the drought passed. Islamic jurists later formulated the concept that all classes were subject to the law of the land, and no person is above the law; officials and private citizens alike have a duty to obey the same law. Furthermore, a Qadi (Islamic judge) was not allowed to discriminate on the grounds of religion, race, colour, kinship or prejudice. In a number of cases, Caliphs had to appear before judges as they prepared to render their verdict. According to Noah Feldman, a law professor at Harvard University, the system of legal scholars and jurists responsible for the rule of law was replaced by the codification of Sharia by the Ottoman Empire in the early 19th century: Economy During the Muslim Agricultural Revolution, the caliphate understood that real incentives were needed to increase productivity and wealth and thus enhance tax revenues. A social transformation took place as a result of changing land ownership giving individuals of any gender, ethnic or religious background the right to buy, sell, mortgage and inherit land for farming or any other purpose. Signatures were required on contracts for every major financial transaction concerning agriculture, industry, commerce and employment. Copies of the contract were usually kept by both parties involved. Early forms of proto-capitalism and free markets were present in the caliphate, since an early market economy and early form of merchant capitalism developed between the 8th and 12th centuries, which some refer to as "Islamic capitalism". A vigorous monetary economy developed based on the circulation of a stable high-value currency (the dinar) and the integration of previously