Muwatta Malik #151

Yahya related to me from Malik from Abd arRahman ibn Abdullah ibn Abd ar-Rahman ibn Abu Sasaca al-Ansari, and later al-Mazini, that his father told him that Abu Said al-Khudri had said to him, "I see that you love sheep and the desert. When you are among your sheep or in your desert, call the prayer and raise your voice in the adhan, because I heard the Messenger of Allah, may Allah bless him and grant him peace, say, 'No jinn or man or anything within range hears the voice of the muadhdhin except that it bears witness for him on the day of rising.' "