Mishkat al-Masabih
Ibn ‘Umar reported God’s Messenger as saying, “If anyone calls the adhan for twelve years, paradise is guaranteed to him; sixty blessings will be recorded for him for every day’s calling of the adhan and thirty blessings for every iqama.” Ibn Majah transmitted it.
وَعَنِ ابْنِ عُمَرَ أَنَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ قَالَ: «مَنْ أَذَّنَ ثِنْتَيْ عَشْرَةَ سَنَةً وَجَبَتْ لَهُ الْجَنَّةُ وَكُتِبَ لَهُ بِتَأْذِينِهِ فِي كُلِّ يَوْمٍ سِتُّونَ حَسَنَةً وَلِكُلِّ إِقَامَة ثَلَاثُونَ حَسَنَة» . رَوَاهُ ابْن مَاجَه
Reference