Sahih Bukhari Volume 004, Book 053, Hadith Number 384.

Narated By 'Umar bin Dinar : I was sitting with Jabir bin Zaid and 'Amr bin Aus, and Bjalla was narrating to them in 70 A.H. the year when Musab bin Az-Zubair was the leader of the pilgrims of Basra. We were sitting at the steps of Zam-zam well and Bajala said, "I was the clerk of Juz bin Muawiya, Al-Ahnaf's paternal uncle. A letter came from 'Umar bin Al-Khattab one year before his death; and it was read: "Cancel every marriage contracted among the Magians between relatives of close kinship (marriages that are regarded illegal in Islam: a relative of this sort being called Dhu-Mahram.)" 'Umar did not take the Jizya from the Magian infidels till 'Abdur-Rahman bin 'Auf testified that Allah's Apostle had taken the Jizya from the Magians of Hajar.