Sahih Muslim 1845 a
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).
حَدَّثَنَا مُحَمَّدُ بْنُ الْمُثَنَّى، وَمُحَمَّدُ بْنُ بَشَّارٍ، قَالاَ حَدَّثَنَا مُحَمَّدُ بْنُ جَعْفَرٍ، حَدَّثَنَا شُعْبَةُ، قَالَ سَمِعْتُ قَتَادَةَ، يُحَدِّثُ عَنْ أَنَسِ بْنِ مَالِكٍ، عَنْ أُسَيْدِ بْنِ حُضَيْرٍ، أَنَّ رَجُلاً، مِنَ الأَنْصَارِ خَلاَ بِرَسُولِ اللَّهِ صلى الله عليه وسلم فَقَالَ أَلاَ تَسْتَعْمِلُنِي كَمَا اسْتَعْمَلْتَ فُلاَنًا فَقَالَ ‏
"‏ إِنَّكُمْ سَتَلْقَوْنَ بَعْدِي أَثَرَةً فَاصْبِرُوا حَتَّى تَلْقَوْنِي عَلَى الْحَوْضِ ‏"‏ ‏.‏