The Book of Oaths
27/11. Chapter:
The reward of a slave who is sincere towards his master and worships Allah properly
Sahih Muslim
حَدَّثَنَا يَحْيَى بْنُ يَحْيَى، قَالَ قَرَأْتُ عَلَى مَالِكٍ عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " إِنَّ الْعَبْدَ إِذَا نَصَحَ لِسَيِّدِهِ وَأَحْسَنَ عِبَادَةَ اللَّهِ فَلَهُ أَجْرُهُ مَرَّتَيْنِ " .
Ibn Umar reported Allah's Messenger (ﷺ) as saying: When a slave looks to the welfare of his master and worships Allah well, he has two rewards for him.
Reference : Sahih Muslim 1664aIn-book reference : Book 27, Hadith 65USC-MSA web (English) reference : Book 15, Hadith 4097