It is narrated from Ibn Shihab that Umar bin Abd al-Aziz asked Abu Bakr bin Sulayman bin Abi Hathmah why, in the time of Abu Bakr al-Siddiq (may Allah be pleased with him), "The Khalifah (successor) of the Messenger of Allah (peace and blessings be upon him)" used to be written, and then Umar al-Faruq (may Allah be pleased with him) at first had "The Khalifah of Abu Bakr" written; so who was the first person to write "Amir al-Mu'minin (Commander of the Believers)"? He said: Al-Shifa' (may Allah be pleased with her), who was among the early women Muhajirun, narrated to me that Umar bin al-Khattab (may Allah be pleased with him) wrote to the governor of Iraq that he should send him two men who were strong and sensible, so that he could get information from them about Iraq and its people. So the governor sent Labid bin Rabi'ah and Adi bin Hatim. When they reached Madinah, they made their mounts kneel in the courtyard of the mosque and entered the mosque, and there they met Amr bin al-As (may Allah be pleased with him). They said: O Amr, seek permission for us to meet the "Amir al-Mu'minin (Commander of the Believers)". Amr bin al-As (may Allah be pleased with him) said: By Allah, the two of you have used exactly the right title: he is the Amir (commander) and we are the Mu'minin (believers). So Amr bin al-As quickly got up, went to Sayyiduna Umar and said: As-salamu alaykum, O Amir al-Mu'minin! Sayyiduna Umar said: O Ibn al-As, how did this title occur to you? My Lord knows that you will have to give an account of what you have said. He said: Labid bin Rabi'ah and Adi bin Hatim have come; they made their mounts kneel in the courtyard of the mosque, then they came to me and said: O Amr, seek permission for us to meet the Amir al-Mu'minin. By Allah, the two of them have called you by exactly the right title: we are all believers and you are our commander. The narrator said: So from that day this title became established in correspondence. And al-Shifa' was the grandmother of Abu Bakr bin Sulayman.