Narrated Abu Sa`id Al-Khudri: Allah's Apostle said, "Whenever you hear the Adhan, say what the Mu'adh-dhin is saying.

Narrated Yahya as above (586) and added: "Some of my companions told me that Hisham had said, "When the Mu'adh-dhin said, "Haiyi `alassala (come for the prayer)." Muawiya said, "La hawla wala quwata illa billah (There is neither might nor any power except with Allah)" and added, "We heard your Prophet saying the same."

Narrated Abu Umama bin Sahl bin Hunaif: I heard Muawiya bin Abi Sufyan (repeating the statements of the Adhan) while he was sitting on the pulpit. When the Mu'adh-dhin pronounced the Adhan saying, "Allahu-Akbar, Allahu Akbar", Muawiya said: "Allah Akbar, Allahu Akbar." And when the Mu'adh-dhin said, "Ash-hadu an la ilaha illal-lah (I testify that none has the right to be worshipped but Allah)", Muawiya said, "And (so do) I". When he said, "Ash-hadu anna Muhammadan Rasulullah" (I testify that Muhammad is Allah's Apostle), Muawiya said, "And (so do) I". When the Adhan was finished, Muawiya said, "O people, when the Mu'adh-dhin pronounced the Adhan I heard Allah's Apostle on this very pulpit saying what you have just heard me saying".