The Book of the Adhan and the Sunnah Regarding It
3/6. Chapter:
Saying The Phrases Of The Iqamah Once
Sunan Ibn Majah
حَدَّثَنَا نَصْرُ بْنُ عَلِيٍّ الْجَهْضَمِيُّ، حَدَّثَنَا عُمَرُ بْنُ عَلِيٍّ، عَنْ خَالِدٍ الْحَذَّاءِ، عَنْ أَبِي قِلاَبَةَ، عَنْ أَنَسٍ، قَالَ أُمِرَ بِلاَلٌ أَنْ يَشْفَعَ، الأَذَانَ وَيُوتِرَ الإِقَامَةَ .
It was narrated that Anas said: "Bilal was commanded to say the phrases of the Adhan twice and the phrases of the Iqamah once."
Reference : Sunan Ibn Majah 730In-book reference : Book 3, Hadith 25English translation : Vol. 1, Book 3, Hadith 730