كتاب الاجارة : Hadeeth No:2130 : Ibn 'Umar:
The Prophet said, "Your example and the example of the people of the
two Scriptures (i.e. Jews and Christians) is like the example of a man
who employed some laborers and asked them, 'Who will work for me from
morning till midday for one Qirat?' The Jews accepted and carried out ...
كتاب الجمعة : Hadeeth No:871 : As-Sa'ib bin Yazid I :
'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).