Then, after his time, injustice spread until people began to commit it openly, and the deterrents of sound judgment were no longer sufficient. To restrain those who seized power by force, they therefore needed an examiner of grievances whose authority was reinforced by the power of the sultanate. The first to designate a specific day for grievances, on which he reviewed the petitions of those wronged—without personally investigating their cases—was ʿAbd al-Malik ibn Marwān. Whenever he encountered a difficult matter or one requiring an enforceable judgment, he referred it to his judge, Abū Idrīs al-Awdī, who would implement his rulings. Thus, Abū Idrīs was the one who directly handled the cases, while ʿAbd al-Malik was the one who issued the orders.

Then the injustice of the governors and the oppression of the tyrannical grew to such an extent that nothing could restrain them except the strongest hand. ʿUmar ibn ʿAbd al-ʿAzīz was therefore the first to take upon himself the adjudication of grievances and to restore to their rightful owners what had been wrongfully taken by the Umayyads. A number of the Abbasid caliphs subsequently sat to hear grievances themselves. The first of them to do so was al-Mahdī, followed by al-Hādī, al-Rashīd, and al-Maʾmūn; the last of them was al-Muhtadī, until properties were restored to their rightful claimants. The Persian kings regarded this as one of the foundations of kingship and one of the laws of justice.