'Abdullah bin Mas'ud (May Allah be pleased with him) reported:
Messenger of Allah (ﷺ) said, "There will be discrimination after my death and there will be other matters that you will disapprove." He was asked: "O Messenger of Allah! What do you command us to do when we are encountered with such happenings?" He answered, "Give what is due from you and supplicate to Allah for your rights."[Al- Bukhari and Muslim].
Arabic/English book reference: Book 1, Hadith 670