Hadith 629
´It was narrated that Ibn 'Umar said:` "At the time of the Messenger of Allah (S.A.W) the phrases of the Adhan were said twice and the phrases of the Iqamah were said once, except that you should say: 'Qad Qamatis-Salah, Qad Qamatis-Salah (prayer is about to begin, prayer is about to begin).'"
Hadith 669
´It was narrated that Abu Al-Muthanna, the Mu'adhdhin of the Jami' Masjid, said:` "I asked Ibn 'Umar about the Adhan and he said: 'At the time of the Messenger of Allah (S.A.W), the phrases of the Adhan were recited twice and the phrases of Iqamah once, except that you should say (the phrase) Qad qamat is-salah (prayer is about to begin)twice. When we heard 'prayer is about to begin' we would perform Wudu' and go out to pray.'"