On Imam Al-kazim’s صلى الله عليه وعلى آله وسلم Clear Appointment of Imam al-Ridha صلى الله عليه وعلى آله وسلم

4-24 In another tradition we read that (The author of the book narrated) my father - may God be pleased with him - narrated that Sa’d ibn Abdillah, on the authority of Muhammad ibn Isa bin Obayd, on the authority of Yunus ibn Abdurrahman, on the authority of Al-Hussein ibn al-Mokhtar, “When Abul Hassan (Imam Al-Kadhim) صلى الله عليه وعلى آله وسلم passed by Basra, we received letters from him صلى الله عليه وعلى آله وسلم in which it was written, ‘My successoris my oldest son (Ali ibn Musa Al-Ridha صلى الله عليه وعلى آله وسلم).’”