Sunan Ibn Majah #729 · The Book of the Adhan and the Sunnah Regarding It

Sunan Ibn MajahIt was narrated that Anas bin Malik said
Sunan Ibn Majah · Book 3 · The Book of the Adhan and the Sunnah Regarding It
Sunan Ibn Majah · كتاب 3 · كتاب الأذان وسننه
"They looked for something by means of which they could call out informing of (the time of) the prayer. Then Bilal was commanded to say the phrases of the Adhan twice and the phrases of the Iqamah once
حَدَّثَنَا عَبْدُ اللَّهِ بْنُ الْجَرَّاحِ، حَدَّثَنَا الْمُعْتَمِرُ بْنُ سُلَيْمَانَ، عَنْ خَالِدٍ الْحَذَّاءِ، عَنْ أَبِي قِلاَبَةَ، عَنْ أَنَسِ بْنِ مَالِكٍ، قَالَ الْتَمَسُوا شَيْئًا يُؤْذِنُونَ بِهِ عِلْمًا لِلصَّلاَةِ فَأُمِرَ بِلاَلٌ أَنْ يَشْفَعَ الأَذَانَ وَيُوتِرَ الإِقَامَةَ ‏.‏
Reference : Sunan Ibn Majah 729In-book reference : Book 3, Hadith 24