(Imām Bukhārī narrates): Muhammad bin Muqatil narrated to us, he said: 'Abdullah informed us, he said: Yunus informed us from al-Zuhri, he said: I heard from Hadhrat al-Sa'ib bin Yazid saying that

on the day of Jumu'ah, the first adhan used to be given when the imam sat on the pulpit, in the time of the Messenger of Allāh ﷺ and in the time of Hadhrat Abu Bakr and Hadhrat 'Umar (may Allāh be pleased with him), when the time of the caliphate of Hadhrat 'Uthman (may Allāh be pleased with him) came and the number of people became very great, Hadhrat 'Uthman ordered the giving of a third adhan, so this adhan used to be given at the place of al-Zawra, then this practice remained established.