Narration of the testimony of Hajar Aswad for Imam Sajjad (a.s) is quite well known among the Imamiyah. There was a dispute between Muhammad bin Hanafiya and Imam Zainul Abideen (a.s) over Imamate. Muhammad claimed that after the martyrdom of Imam Husain (a.s), the Imamate has been entrusted to him. Imam Sajjad (a.s) also argued with him on the basis of the verse: “…and the possessors of relationships are nearer to each other…” (8:75) Interpretation of this verse is in favor of Imamate of Imam Sajjad (a.s) and his descendants. Then Imam Sajjad (a.s) said: I argue with you through Hajar Aswad [and leave the judgment to it]. Muhammad bin Hanafiyyah asked: How can you argue with me through a stone, which can neither hear nor reply? Imam (a.s) reminded him that Hajar Aswad can adjudge between them; so they agreed on going to the Kaaba to decide (the matter) by the Black Stone. Imam Zainul Abideen (a.s) said to Muhammad Hanafiyyah: Go ahead and speak to Hajar Aswad. Muhammad came forward and stood besides Hajar Aswad and spoke to it, then he fell silent, but Hajar Aswad did not reply. Then Ali bin Husain (a.s) came forward and placed his hand on Hajar Aswad and then supplicated: “O Allah, I ask You by Your name written on the canvas of glory.” The Imam supplicated and said: “O Allah, make this stone speak.” Then he addressed Hajar Aswad: “I call you in the name of one who has reposed the covenants of people in you and made you the testimony of those who come to you, I adjure you to inform to whom Imamate and successorship of the Messenger of Allah (s) belongs?”