"How wonderful it is for one of them that he obeys Allah and fulfills the rights of his master." Meaning the slave. And Ka'b said: "Allah and His Messenger spoke the truth."  

أَنَّ رَسُولَ اللَّهِ ﷺ قَالَ نِعِمَّا لأَحَدِهِمْ أَنْ يُطِيعَ رَبَّهُ وَيُؤَدِّيَ حَقَّ سَيِّدِهِ يَعْنِي الْمَمْلُوكَ وَقَالَ كَعْبٌ صَدَقَ اللَّهُ وَرَسُولُهُ وَفِي الْبَابِ عَنْ أَبِي مُوسَى وَابْنِ عُمَرَ  

"There shall be upon dunes of musk- I think he said: On the Day of Judgment- a slave who fulfills Allah's right and the right of his patron (master), a man who leads a people (in prayer) and they are pleased with him. And a man who calls for the five prayers during every day and night."  

قَالَ رَسُولُ اللَّهِ ﷺ ثَلاَثَةٌ عَلَى كُثْبَانِ الْمِسْكِ أُرَاهُ قَالَ يَوْمَ الْقِيَامَةِ عَبْدٌ أَدَّى حَقَّ اللَّهِ وَحَقَّ مَوَالِيهِ وَرَجُلٌ أَمَّ قَوْمًا وَهُمْ بِهِ رَاضُونَ وَرَجُلٌ يُنَادِي بِالصَّلَوَاتِ الْخَمْسِ فِي كُلِّ يَوْمٍ وَلَيْلَةٍ