From Sahih Muslim (Hadith 4779):
It has been narrated on the authority of Usaid b. Hudair that a man from the Ansar took the Messenger of Allah (ﷺ) aside and said to him:Will you not appoint me governor as you have appointed so and so? He (the Messenger of Allah) said: You will surely come across preferential treatment after me, so you should be patient until you meet me at the Cistern (Haud-i-Kauthar)
Reference: Muslim 4779