"The Mu'adhdhin will be forgiven as far as his voice reaches, and every wet and dry thing will bear witness for him."
Sunan an-Nasa'i Book 7, Hadith 20
← Previous Hadith "I see that you love sheep and the desert. When you are with your sheep or in the desert and you call the Adhan for prayer, then raise your voice, for no human, Jinn or anything else hears the voice of the Mu'adhdhin as far as it reaches, but it will bear witness for him on the Day of Resurrection." Abu Sa'eed said: "I heard it from the Messenger of Allah (S.A.W)."

Sunan an-Nasa'i Book 7, Hadith 19 Next Hadith → "Allah and His angels say salah upon the front rows, and the Mu'adhdhin will be forgiven as far as his voice reaches, and whatever hears him, wet or dry, will confirm what he says, and he will have a reward like that of those who pray with him."

Sunan an-Nasa'i Book 7, Hadith 21