"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).'"
Sunan an-Nasa'i Book 7, Hadith 3
← Previous Hadith "The Messenger of Allah (S.A.W) commanded Bilal to say the phrases of the Adhan twice and the phrases of the Iqamah once."

Sunan an-Nasa'i Book 7, Hadith 2 Next Hadith → "Recite it to me." He said, "Allahu Akbar, Allahu Akbar (Allah is the greatest, Allah is the greatest), Ashhadu an la ilaha illallah (I bear witness that there is none worthy of worship except Allah) - twice. Ashhadu anna Muhammadan Rasulallah (I bear witness that Muhammad is the messenger of Allah) - twice. Then he said in a lower voice which those around him could here: Ashhadu an la ilaha ill-Allah (I bear witness that there is none worthy of worship except Allah) - twice. Ashhadu anna Muhammadan Rasulallah (I bear witness that Muhammad is the messenger of Allah) - twice, Hayya'ala as-salah (come to prayer) - twice, Hayya alal-falah (come to prosperity) - twice, Allahu Akbar Allahu Akbar la ilaha illallah (Allah is the Greatest, Allah is the Greatest, there is none worthy of worship except Allah).

Bishir bin Mu'adh who heard it from Ibrahim, and from whom An-Nasa'i is reporting it, is the one who is asking for the Adhan to be recited to him.

Sunan an-Nasa'i Book 7, Hadith 4