Narrated Abu Qilaba:Anas said, "Bilal was ordered to pronounce the wording of Adhan twice and of Iqama once only." The sub narrator Isma`il said, "I mentioned that to Aiyub and he added (to that), "Except Iqama (i.e. Qad-qamat-is-salat which should be said twice)

English translation · Sahih al-Bukhari