Sahih Adab al-Mufrad

784/1023- (Authentic chain of narration) From Ibn Shihab: That Umar ibn Abd al-Aziz asked Abu Bakr ibn Sulayman ibn Abi Hathmah: Why did Abu Bakr write: From Abu Bakr; the Caliph of the Messenger of Allah. Then after him, Umar wrote: From Umar ibn al-Khattab; the Caliph of Abu Bakr. Who was the first to write: Commander of the Believers (Amir al-Mu'minin)? He said: My grandmother al-Shifa’ told me—and she was among the first emigrant women, and Umar ibn al-Khattab, may Allah be pleased with him, whenever he entered the market, he would enter upon her—she said: "Umar ibn al-Khattab wrote to the governor of the two Iraqs: Send me two strong and noble men; I want to ask them about Iraq and its people. So the governor of the two Iraqs sent him Labid ibn Rabi‘ah and ‘Adi ibn Hatim. They arrived in Medina, tied their mounts in the courtyard of the mosque, then entered the mosque and found ‘Amr ibn al-‘As. They said to him: O ‘Amr! Seek permission for us to enter upon the Commander of the Believers; Umar. So ‘Amr jumped up and entered upon Umar. He said: Peace be upon you, O Commander of the Believers! Umar said: What made you use this title, O son of al-‘As? You must explain what you said. He said: Yes, Labid ibn Rabi‘ah and ‘Adi ibn Hatim arrived and said to me: Seek permission for us to enter upon the Commander of the Believers. I said: By Allah, you have named him rightly, for he is the commander, and we are the believers. So from that day, the title was used in correspondence."

785/1024- (Authentic chain of narration) from Ubayd Allah ibn Abdullah(2) who said: Muawiya came for Hajj, his first Hajj while he was Caliph, and Uthman ibn Hunaif al-Ansari entered upon him and said: Peace be upon you, O Amir, and the mercy of Allah. The people of Sham found this strange and said: Who is this hypocrite who shortens the greeting to the Commander of the Believers? Uthman then knelt on his knee and said: O Commander of the Believers! These people have found fault with me for something you know better than they do. By Allah, I greeted Abu Bakr, Umar, and Uthman with this greeting, and none of them found fault with it. Muawiya then said to those from the people of Sham who spoke: "Take it easy; indeed, some of what he says is true, but the people of Sham have been affected by these tribulations. They say: Do not shorten the greeting to our Caliph; and I think, O people of Madinah, that you say to the collector of charity: O Amir."

786/1025- (Authentic chain) From Jabir who said: "I entered upon al-Hajjaj, and I did not greet him with salam."

787/1026- (Authentic chain) From Tamim ibn Huzlam who said: I remember the first one who gave salam to someone with the title of leadership in Kufa. Al-Mughira ibn Shu’ba came out from the Rahba gate, and a man from Kindah— they claimed he was Abu Qurrah al-Kindi— met him and greeted him. He said: Peace be upon you, O commander, and the mercy of Allah, peace be upon you. He disliked it. So he said: Peace be upon you, O commander, and the mercy of Allah, peace be upon you. Am I not one of them, or not? Simak said: "Then he later acknowledged it."