It was narrated that Abu Hurairah said:"I heard the Messenger of Allah himself say: 'The Mu'adh-dhin's sins will be forgiven as far as his voice reaches, and every wet and dry thing will pray for forgiveness for him. For the one who attends the prayer, twenty-five Hasanat (good deeds) will be recorded, and it is will be expiation (for sins committed) between them (the two prayers).'"
حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا شَبَابَةُ، حَدَّثَنَا شُعْبَةُ، عَنْ مُوسَى بْنِ أَبِي عُثْمَانَ، عَنْ أَبِي يَحْيَى، عَنْ أَبِي هُرَيْرَةَ، قَالَ سَمِعْتُ مِنْ، فِي رَسُولِ اللَّهِ ـ صلى الله عليه وسلم ـ يَقُولُ " الْمُؤَذِّنُ يُغْفَرُ لَهُ مَدَّ صَوْتِهِ وَيَسْتَغْفِرُ لَهُ كُلُّ رَطْبٍ وَيَابِسٍ وَشَاهِدُ الصَّلاَةِ يُكْتَبُ لَهُ خَمْسٌ وَعِشْرُونَ حَسَنَةً وَيُكَفَّرُ عَنْهُ مَا بَيْنَهُمَا " .
IbnMaja
The Book of the Adhan and the Sunnah Regarding It • Hadith 724