Ibn Mas'ud (May Allah be pleased with him) reported:
Messenger of Allah (ﷺ) said, "You will see after me favouritism and things which you will disapprove of." They submitted: "What do you order us to do (under such circumstances)?" He replied, "Discharge your obligations and ask your rights from Allah".[Al-Bukhari and Muslim]. (DE)
Arabic/English book reference (DE): Book 1, Hadith 51 (DE)