Hadith 1674
Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) narrates: In the time of the Prophet (peace and blessings of Allah be upon him), the words of the adhan were said twice and the iqamah was said once, however, «قد قامت الصلوۃ» was said twice. When we heard the iqamah, we would perform ablution and come for the prayer.
Hadith 1675
Sayyiduna Anas (may Allah be pleased with him) narrates: Sayyiduna Bilal (may Allah be pleased with him) was commanded to say the words of the adhan in even numbers and the words of the iqamah in odd numbers. (Imam Ibn Hibban, may Allah have mercy on him, says:) None of the trustworthy narrators have transmitted this narration from Shu’bah except Muhammad bin Ayyub Razi and Abu Khalifah, as referenced by Ibn Kathir.