Abu Hurairah Radiyallahu 'anhu narrated that Nabi Sallallahu 'alaihi wasallam said: The Muadhdhin will recieve forgivness to the distance to which his voice reaches. All living and non-living things shall bear witness for him on the Day of Resurrection. He, who attends Salat in congregation, for him is written the reward of twenty five Salat, and it becomes an atonement for his sins between two Salat (Abu Dawud)
Note: According to some Scholars the reward of twenty-five Salat is for the Muadhdhin, and he gets forgiveness of his sins from the previous Adhan to this Adhan. (Badhl-ul-Majhud)
Ibn 'Umar Radiyallahu 'anhuma narrates that Rasullullah Sallallahu 'alaihi wasallam said: The Muadhdhin will receive forgiveness to the extent the voice of his Adhan reaches; every living and non-living thing that hears his voice, supplicates for his forgiveness. In another narration it is stated: Every living and non-living thing replies to his Adhan. (Musnad Ahmad, Tabarani, Bazzar, Majma'uz-Zawaid)
Abu Sa'sa'ah Radiyallahu 'anhu narrates that Abu Sa'id Radiyallahu 'anhu said: When you are in a desert or countryside, then call the Adhan loudly, as I have heard Rasullullah Sallallahu 'alaihi wasallam saying: No tree or clod of earth, or rock, or Jinn, or man shall hear his voice; except that they will bear witness for him on the Day of Resurrection. (Ibn Khuzaimah)
Bara Ibn 'Azib Radiyallahu 'anhuma narrates that Nabi Sallallahu 'alaihi wasallam said: Verily, Allah and His angels send blessings upon the persons of the first row. The one who calls Adhan receives forgiveness to the extent to which he raises his voice. All living and non-living things, who hear his call, testify to it. And for him is a reward equivalent to all those who perform Salat with him. (Nasal)
Note: One interpretation of the second sentence of this hadith is that the Muadhdhin shall receive forgiveness for his sins to the extent that his voice reaches. Another interpretation is that the sins of the people living within the range of his voice will be forgiven by virtue of his intercession. (Badhl-ul-Majhud)
Mu'awiya Radiyallahu 'anhu narrates: I heard Rasullullah Sallallahu 'alaihi wasallam saying: The Muadhdhins will have the longest necks amongst the people on the Day of Resurrection. (Muslim)
Note: Islamic Scholars have mentioned several interpretations to this hadith:
1. As people go to the masjid to offer Salat in response to the Adhan of the Muadhdhin, it is as though he is their leader and they are his followers. A leader is like a chief who has a long neck, which makes his head prominent.
2. The Muadhdhin shall raise his head high, longing to gaze at his magnificent reward, thus giving the appearance of the longest neck.
3. The Muadhdhin shall hold his head high as he has nothing to regret by virtue of his calling the Adhan. Whereas the one who regrets, or is ashamed of his actions, lowers his head in humility and shame.
4. The longest neck is an allegorical description, depicting the Muadhdhin as the most prominent of all on the Plain of Reckoning. Still others have mentioned that the Muadhdhins will proceed speedily towards Paradise. (Nawawi)
Ibn 'Umar Radiyallahu 'anhuma narrates that Nabi Sallallahu 'alaihi wasallam said: He who calls the Adhan for twelve years, Paradise is guaranteed for him and sixty blessings will be recorded for every Adhan, and thirty blessings will be recorded for every Iqamah. (Mustadrak Hakim)
Ibn 'Umar Radiyallahu 'anhuma narrates that Rasullullah Sallallahu 'alaihi wasallam said: Three persons shall neither be terrified by the greatest horror of the Day of Resurrection, nor shall they be made to render an account of their deeds, (and) they will be upon mounds of Musk until the reckoning of creation is completed. One who recites the Qur'an only to please Allah and leads Salat in a manner pleasing to his followers. The other is he who calls towards Salat, only to please Allah. And the third is he who maintains a good relationship with his Rabb, and also with his subordinates. (Tirmidi, Tabarani, Majma'uz-Zawaid)
'Abdullah Ibn 'Umar Radiyallahu 'anhuma narrates that Rasullullah Sallallahu 'alaihi wasallam said: Three persons will be upon mounds of Musk on the Day of Resurrection, envied by all the former and latter people. The man who calls Adhan for the five times Salat during the day and night; and the man who leads the Salat in a manner that people are pleased with him; and a slave who had fulfilled the rights of Allah and the rights of his master. (Tirmidi)
Abu Hurairah Radiyallahu 'anhu narrates that Rasullullah Sallallahu 'alaihi wasallam said: The Imam is responsible and the Muadhdhin is entrusted. O Allah! Guide the Imams and forgive the Muadhdhins. (Abu Dawud)
Note: The Imam is responsible, means that besides his personal Salat, he bears the responsibility of the Salat of those behind him. Therefore the Imam should perfect his Salat as far as is humanly possible both outwardly and inwardly. In the light of this important responsibility, Rasullullah Sallallahu 'alaihi wasallam made a Du'a for the guidance of the Imams. The Muadhdhin is entrusted means that people have placed their trust on the Muadhdhin regarding the timings of the Salat and Saum. Therefore, it is essential for the Muadhdhin to be particular in calling the Adhan at its proper time. However, being human, he may inadvertently err. Hence, Rasullullah Sallallahu 'alaihi wasallam has made a Du'a for his forgiveness. (Badhl-ul-Majhud)