(470) بَابُ التَّسْلِيمِ عَلَى الأَمِيرِ
'Umar ibn 'Abdu'l-'Aziz asked Abu Bakr ibn Abi Hathama, "Why didAbu Bakr write, 'From Abu Bakr, the Khalifa (Successor) of the Messengerof Allah' and then 'Umar wrote after him, 'From 'Umar ibn al-Khattab, thekhalifa (successor) of Abu Bakr'? Who was the first to write 'the Amiral-Mu'minin'?" He replied, "My grandmother, ash-Shifa', related to me,and she was one of the first to write 'the Amir al-Mu'minin'?" He said,"My grandfather, ash-Shifa' related to me, (and she was one of the firstMuhajirun and when 'Umar ibn al-Khattab entered the market, he visitedher), saying, ''Umar ibn al-Khattab wrote to the governor of Iraq requestinghim to send him two trustworthy noble men so that he could question themabout Iraq and its people. He sent him a master of Iraq, Labid ibn Rabi'aand also 'Adi ibn Hatim, and they came to Madina. They made their camelskneel in the courtyard of the mosque, entered it and found 'Amr ibn al-'As.They said to him, ''Amr, ask permission for us to visit the Amir al-Mu'minin,'Umar.' 'Amr got up and went to 'Umar. He said, 'Peace be upon you, Amiral-Mu'minin.' 'Umar said to him, 'Ibn al-'As, what made you use this name?You have deviated from what you normally say.' He said, 'Yes, Labid ibnRabi'a and 'Adi ibn Hatim came and said to me, "Ask permission for us tovisit the Amir al-Mu'minin." I said, "You two, by Allah, have hit uponthe correct name. He is the amir and we are the believers."' The titleoriginated on that day."
Reference: Al-Adab Al-Mufrad 1023
In-book reference: Book 42, Hadith 60
English translation: Book 42, Hadith 1023