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.