كتاب الأيمان
27  
The Book of Oaths
(11)
Chapter: The reward of a slave who is sincere towards his master and worships Allah properly
(11)
باب ثَوَابِ الْعَبْدِ وَأَجْرِهِ إِذَا نَصَحَ لِسَيِّدِهِ وَأَحْسَنَ عِبَادَةَ اللَّهِ ‏‏
Sahih Muslim 1665 b

This hadith has been transmitted on the authority of Abu Tahir but with a slight variation of words.

وَحَدَّثَنِيهِ زُهَيْرُ بْنُ حَرْبٍ، حَدَّثَنَا أَبُو صَفْوَانَ الأُمَوِيُّ، أَخْبَرَنِي يُونُسُ، عَنِ ابْنِ شِهَابٍ، بِهَذَا الإِسْنَادِ وَلَمْ يَذْكُرْ بَلَغَنَا وَمَا بَعْدَهُ ‏.‏
Reference : Sahih Muslim 1665b
In-book reference : Book 27, Hadith 68
USC-MSA web (English) reference : Book 15, Hadith 4099
  (deprecated numbering scheme)