كتاب الإمارة
33
The Book on Government
(5)
Chapter: The virtue of a just ruler and the punishment of a tyrant; Encouragement to treat those under one's authority with kindness and the prohibition against causing them hardship
(5)
باب فَضِيلَةِ الإِمَامِ الْعَادِلِ وَعُقُوبَةِ الْجَائِرِ وَالْحَثِّ عَلَى الرِّفْقِ بِالرَّعِيَّةِ وَالنَّهْيِ عَنْ إِدْخَالِ الْمَشَقَّةِ عَلَيْهِمْ

It has been narrated on the authority of Hasan that A'idh b. 'Amr who was one of the Companions of the Messenger of Allah (ﷺ) called on 'Ubaidullah b. Ziyad and said (to him):

O my son, I have heard the Messenger of Allah (ﷺ) say: The worst of guardians is the cruel ruler. Beware of being one of them. Ubaidullah said (to him out of arrogance): Sit you down. You are from the chaff of the Companions of Muhammad (ﷺ). A'idh said: Was there worthless chaff among them? Such worthless chaff appeared after them and among other people.
حَدَّثَنَا شَيْبَانُ بْنُ فَرُّوخَ، حَدَّثَنَا جَرِيرُ بْنُ حَازِمٍ، حَدَّثَنَا الْحَسَنُ، أَنَّ عَائِذَ بْنَ عَمْرٍو، - وَكَانَ مِنْ أَصْحَابِ رَسُولِ اللَّهِ صلى الله عليه وسلم - دَخَلَ عَلَى عُبَيْدِ اللَّهِ بْنِ زِيَادٍ فَقَالَ أَىْ بُنَىَّ إِنِّي سَمِعْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم يَقُولُ ‏ "‏ إِنَّ شَرَّ الرِّعَاءِ الْحُطَمَةُ فَإِيَّاكَ أَنْ تَكُونَ مِنْهُمْ ‏"‏ ‏.‏ فَقَالَ لَهُ اجْلِسْ فَإِنَّمَا أَنْتَ مِنْ نُخَالَةِ أَصْحَابِ مُحَمَّدٍ صلى الله عليه وسلم ‏.‏ فَقَالَ وَهَلْ كَانَتْ لَهُمْ نُخَالَةٌ إِنَّمَا كَانَتِ النُّخَالَةُ بَعْدَهُمْ وَفِي غَيْرِهِمْ ‏.‏
Reference : Sahih Muslim 1830
In-book reference : Book 33, Hadith 32
USC-MSA web (English) reference : Book 20, Hadith 4504
  (deprecated numbering scheme)