Abu Ja’far Muhammad ibn ‘Ali, peace upon him, who reported from his father, who reported from his grandfather that:
Allah sent Jibraeel to Muhammad, peace be upon him and his progeny, exhorting him to testify the wilayah of ‘Ali ibn Abi Talib (A.S.) in his lifetime, and to name him Amirul Mu’mineen before his death. Then the Prophet, peace be upon him and his progeny, invited nine leaders (of the groups) and said: “I have invited you so that you may bear witness upon the earth in the name of Allah, whether you stand by it or hide it.”
Then he said: “O Abu Bakr, Rise and greet ‘Ali as Amirul Mu’mineen (the Commander of the faithfuls).” He said: “Is this by the order of Allah and His Prophet?” He said: “Yes”. So he stood and greeted him as such (i.e. Amirul Mu’mineen).
Then he said: “O Umar, Rise and greet ‘Ali as Amirul Mu’mineen.” He said: “Should we name him as Amirul Mu’mineen by the order of Allah and His Prophet?” He said: “Yes”. So he rose and greeted him.
Then he turned to Miqdad ibn al-Aswad al-Kindi: “Rise and greet ‘Ali as Amirul Mu’mineen.” He stood up and greeted him, without repeating what the earlier two had said.
Then he said to Abu Dharr al-Ghifari: “Rise and greet ‘Ali as Amirul Mu’mineen.” He stood up and greeted. Then he asked Hudhaifa al-Yamani: “Rise and greet Amirul Mu’mineen.” He stood up and greeted. The he asked Ammar ibn Yasir: “Rise and greet Amirul Mu’mineen.” He stood up and greeted. Then he asked Buraidah: “Rise and greet Amirul Mu’mineen.” Buraidah was the youngest among them, he stood up and greeted.
Then the Prophet, peace be upon him and his progeny, said: “I have invited you for this matter, so that you are Allah’s witnesses, whether you uphold it or abandon it.”