Tacit and Explicit Testimony as proof of abu al-Hassan Musa’s  عليه السلام Divine Authority over the people after abu ‘Abdallah  عليه السلام — report 13

13. Ali ibn Muhammad has narrated from Sahl or an other person, from Muhammad ibn al-Walid from Yunus from Dawud ibn Zurbi from abu Ayyub al-Nahwi who has said the following. “Abu Ja‘far, al-Mansur summoned me in the middle of the night and I went to see him. When met him he was sitting in a chair. Before him there was a candle and a letter in his hand. The narrator has said that I greeted him and he threw the letter to me while was weeping. He said, “This is a letter of Muhammad ibn Sulayman in which he has informed us that abu Ja‘far ibn Muhammad عليه السلام has died. We are for Allah and to Him we will all return. He said it three times. Where is anyone like Ja‘far? “ Then he said to me, “Write down.” The narrator has said that I then wrote. I wrote the introduction of the letter. He (Mansur) said, “Write to ask if he has left a directive will to any man particularly, if so summon him and kill him.” He has said that reply to hisletter came back that said the Imam عليه السلام has in fact, left a will to five people and one of them is abu Ja‘far al-Mansur, Muhammad ibn Sulayman, ‘Abdallah, Musa and Hamida.”