'Allama Majlisi, in his Bihar al-anwar, writes: When Muhammad b. 'Uthman became seriously ill, a group of prominent Shi'is like Abu 'Ali b. Humam, Abu 'Abd Allah b. Muhammad Katib, Abu 'Abd Allah Baqtani, Abu Sahl Nawbakhti, and Abu 'Abd Allah b. Wajna' came to see him. They asked him about his successor. In reply he said: "Husayn b. Ruh is my successor and the trusted deputy of the Master of the Age. Refer to him in your affairs. I have been commanded by the Imam to designate Husayn b. Ruh in the position of deputyship."
Ja'far b. Muhammad Mada'ini relates that he used to carry the goods that belonged to the Imam to Muhammad b. 'Uthman. One day he took four hundred dinars to him. Muhammad b. 'Uthman asked him to deposit it with Husayn b. Ruh and so Ja'far asked him the reason he did not accept it himself. Muhammad b. 'Uthman said: "Take it to Husayn b. Ruh. You should know that I have appointed him as my successor." Ja'far went on to ask if he had done so under instructions from the Imam. He replied: "Yes." Hence, Ja'far took the money to Husyan b. Ruh and from this time on he deposited the Imam's share with the latter.
Among the companions and close associates of Muhammad b. 'Uthman there were a number of people, such as Ja'far b. Ahmad b. Matil, who held much higher position in merits than Husyan b. Ruh. In fact, many thought that the deputyship would be given to Ja'far Matil. However, contrary to the generally held expectation, it was Husayn b. Ruh who became the next deputy. Everyone at that point submitted to Muhammad b. 'Uthman's decision, including Ja'far Matil. Abu Sahl Nawbakhti was asked about this decision: "How did Husayn b. Ruh get appointed to the position of deputyship, when you were more qualified to assume it?" In response he said: "The Imam knows better about the person who can represent him. I am always in debate with our opponents. If I were the deputy, maybe at the time of heated debate, in order to prove my point, I would have revealed the Imam's whereabouts. But Husayn b. Ruh is not like me. If he had the Imam hidden under his garments, and if he were being cut to pieces, he would not expose him to anyone."
Shaykh Saduq relates the circumstances that led his father to write a letter to the Imam and ask him to pray for a son for him. According to this report, it was Muhammad b. 'Ali Aswad who related that Shaykh Saduq's father, 'Ali b. Husyan b. Babawayh, sent a message through him to Husyan b. Ruh to ask the Imam to pray for a son for him. That message was delivered to Husayn b. Ruh. After three days he informed Muhammad Aswad that the Imam had prayed for him and that in the near future God would favor him with a son. That very year Muhammad, that is Shaykh Saduq, was born. After that several other sons were born. But it was Shaykh Saduq who used to pride himself on having been born through the special prayer of the Imam. In fact, whenever Muhammad Aswad saw Shaykh Saduq in the learning sessions with prominent teachers, studying extremely well, he would say: "It is not surprising to see you studying so well. After all you were born through the prayer of the Imam of the Age!"
There was a man who had doubts about the deputyship of Husayn b. Ruh. For clarification of his doubt he wrote a letter to the Imam with a dry pen without ink. After a few days he received a reply from the Hidden Imam (peace be upon him) through Husayn b. Ruh. Husayn b. Ruh died in the month of Sha'ban, in the year 326 AH/937 CE.
Muhammad b. 'Uthman the Second Deputy of the Occulted Imam Al Mahdi
