(16) باب الْعَبْدِ إِذَا أَحْسَنَ عِبَادَةَ رَبِّهِ وَنَصَحَ سَيِّدَهُ
Narrated Ibn `Umar:
Allah's Messenger (ﷺ) said, "If a slave is honest and faithful to his master and worships his Lord (Allah) in a perfect manner, he will get a double reward."
Reference: Sahih al-Bukhari 2546
In-book reference: Book 49, Hadith 30
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 3, Book 46, Hadith 722