4-16 In another tradition it is narrated that (The author of the book narrated) my father - may God be pleased with him - narrated that Sa’d ibn Abdullah quoted on the authority of Ahmad ibn Muhammad ibn Isa, on the authority of Ali ibn al-Hakam, on the authority of Haydar ibn Ayyoub, “We were in a place known as Qaba in Medina where Muhammad ibn Zayd ibn Ali lived. Muhammad came later than usual. We asked him, ‘May we be your ransom! What kept you from coming on time?’ He said, ‘Abu Ibrahim (s) invited seventeen men from the descendants of Ali (s) and (the Blessed Lady) Fatima (s). He had us bear witness that his son Ali is his Testamentary Trustee and deputy in his lifetime and after his death and that he accepts Ali’s decrees against him or in favor of him.’ Muhammad ibn Zayd continued, ‘O Haydar (ibn Ayyoub)! By God, today he appointed him as the Imam. The Shiites will follow him from today. Haydar said, ‘What are you saying? God will keep him alive.’ Muhammad (ibn Zayd) said, ‘O Haydar (ibn Ayyoub)! Once he (s) appointed his son (Ali) as his Testamentary Trustee, he has established Ali (s) as the Imam.’ Ali ibn al-Hakam said, ‘Haydar (ibn Ayyoub) passed away while he was still in doubt.’