Sahih al-Bukhari 915
Sahih al-Bukhari · Book 11: Friday Prayer · To sit on the pulpit while Adhan is pronounced
Narrated As-Sa'ib bin Yazid I:
حَدَّثَنَا يَحْيَى بْنُ بُكَيْرٍ ، قَالَ حَدَّثَنَا اللَّيْثُ ، عَنْ عُقَيْلٍ ، عَنِ ابْنِ شِهَابٍ ، أَنَّ السَّائِبَ بْنَ يَزِيدَ ، أَخْبَرَهُ أَنَّ التَّأْذِينَ الثَّانِيَ يَوْمَ الْجُمُعَةِ أَمَرَ بِهِ عُثْمَانُ حِينَ كَثُرَ أَهْلُ الْمَسْجِدِ، وَكَانَ التَّأْذِينُ يَوْمَ الْجُمُعَةِ حِينَ يَجْلِسُ الإِمَامُ.
`Uthman bin `Affan introduced the second Adhan on Fridays when the number of the people in the mosque increased. Previously the Adhan on Fridays used to be pronounced only after the Imam had taken his seat (on the pulpit).