"Three shall be on dunes of musk" - it seems to me that he said:- "on the Day of Resurrection. The first and the last of peoples shall envy them: A man who calls to the five [prayers] every day and night; a man who leads a group of people and they are pleased with him, and a slave who fulfills the right of Allah and the right of his masters."  

قَالَ رَسُولُ اللَّهِ ﷺ ثَلاَثَةٌ عَلَى كُثْبَانِ الْمِسْكِ أُرَاهُ قَالَ يَوْمَ الْقِيَامَةِ يَغْبِطُهُمُ الأَوَّلُونَ وَالآخِرُونَ رَجُلٌ يُنَادِي بِالصَّلَوَاتِ الْخَمْسِ فِي كُلِّ يَوْمٍ وَلَيْلَةٍ وَرَجُلٌ يَؤُمُّ قَوْمًا وَهُمْ بِهِ رَاضُونَ وَعَبْدٌ أَدَّى حَقَّ اللَّهِ وَحَقَّ مَوَالِيهِ  

"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." (Using translation from Tirmidhī 1986)   

قَالَ رَسُولُ اللهِ ﷺ ثَلَاثَةٌ عَلَى كُثْبَانِالْمِسْكِ يَوْمَ الْقِيَامَةِ رَجُلٌ أَمَّ قَوْمًا وَهُمْ بِهِ رَاضُونَ وَرَجُلٌ يُؤَذِّنُ فِي كُلِّ يَوْمٍ وَلَيْلَةٍ خَمْسَ صَلَوَاتٍ وَعَبْدٌ أَدَّى حَقَّ اللهِ تَعَالَى وَحَقَّ مَوَالِيهِ  

"ثَلَاثَةٌ عَلَى كُثبانِ الْمِسْكِ يَوم القيامةِ - يَغْبِطُهُم الأَولُونَ وَالآخِرُونَ: عبدٌ أَدَّى حقَّ اللَّه وَحَقَّ مَوَاليهِ، وَرَجُلٌ يَؤُمُّ قَوْمًا وَهُم بِهِ رَاضُونَ، ورجُلٌ يُنَادِى بالصَّلَوَاتِ الْخَمْسِ في كُلِّ يَوْم وَليْلَة".