General Behavior (Kitab Al-Adab)
43/135. Chapter:
If a slave is sincere
Sunan Abi Dawud
حَدَّثَنَا عَبْدُ اللَّهِ بْنُ مَسْلَمَةَ الْقَعْنَبِيُّ، عَنْ مَالِكٍ، عَنْ نَافِعٍ، عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " إِنَّ الْعَبْدَ إِذَا نَصَحَ لِسَيِّدِهِ وَأَحْسَنَ عِبَادَةَ اللَّهِ فَلَهُ أَجْرُهُ مَرَّتَيْنِ " .
‘Abd Allah b. ‘Umar reported the Messenger of Allah (May peace be upon him) as saying: when a slave acts sincerely towards his master and worship Allah well, he will have a double reward.
Reference : Sunan Abi Dawud 5169In-book reference : Book 43, Hadith 397English translation : Book 42, Hadith 5150