Hadith
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 " .
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)
Sahih · Al-Albani
Sunan Ibn Majah 724 ·Book 3, Hadith 19·Also available on sunnah.com·