3 groups of people will be on mountains of musk on the Day of Qiyaamah.

عَنْ عَبْدِ اللَّهِ بْنِ عَمَرَ رَضِيَ اللَّهُ عَنْهُمَا قَالَ قَالَ رَسُولُ اللَّهِ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ ثَلَاثَة عَلَى كَتَبَانِ الْمِسْكِ أَرَاهُ قَالَ يَوْمَ الْقِيَامَةِ يَغْبِطُهُمُ الْأَوَّلُونَ وَالْآخِرُونَ رَجُلٌ يُنَادِي بِالصَّلَوَاتِ الْخَمْسِ فِي كُلِّ يَوْمِ وَلَيْلَةٍ وَرَجُلٌ يَؤم قَوْمًا وَهُمْ بِهِ رَاضُونَ وَعَبْد أَدَى حَقَّ اللهِ وَحَقَّ مَوَالِيهِ (سنن الترمذي، الرقم: ٢٥٦٦)

Hazrat Abdullah bin Umar (Radiyallahu anhu) reports that  Rasulullah (Sallallahu alayhi wasallam) said, “Three groups of people will be on mountains of musk (on the Day of Qiyaamah), and the former and latter people will envy their position. 

The first is the person who used to call out the azaan every day for the five daily salaah. 

The second is the person who led the people in salaah while they were pleased with him (i.e. he fulfilled the obligation of salaah in its proper manner). 

The third is the slave who fulfilled therights of Allah Ta'ala and the rights of his masters.”