Whatever he says to you he says so on my behalf...
Whatever he says to you he says so on my behalf, and what ever he does he does on my behalf." Likewise, with this certificate of admiration, he became the deputy (Ni’ibu ‘l-Imam) of the Twelfth Imam after the demise of Imam Hasan al-’Askari (a.s.). On the death of Abu ‘Umari, the Lord of the Age (Sahibu-z-Zaman) himself sent condolences to his son, Muhammad ibn ‘Uthman saying: "Verily, we'd belong to Allah and verily to Him shall we return.
We submit to His command and are pleased with His decree. Your father has lived in good fortune and has died with dignity. May Allah’s mercy be upon him, he has joined his friends and masters. He was always endeavouring to search for whatever would bring him near to Allah and His friends. May Allah make strengthen his countenance." Abu Ja’far Muhammad ibn ‘Uthman: This man was the second special deputy of Imam-e Zaman.
He was also a deputy of the Eleventh Imam about whom the latter said: "The greatness of his dignity and the exaltation of his status among the Shi’ites is so famous that these is no need to explain or dispute it." Regarding him and his father, ‘Uthman ibn Sa’id, Imam Hasan al-’Askari (a-s.) said to one of his companions: "Umar and his son are both trustworthy. Whatever they do they do on my behalf, and whatever they say to you, they say so on my behalf.
Therefore, listen to their words and obey them, because both of them are reliable and trustworthy to us." And Imam-e- Zaman himself said about him: "He is my confident, and his letter is of the same status as mine." Abul-Qasim Husayn ibn Ruh Nawbakhti: Abi Ja’far Muhammad ibn ‘Uthman, the third deputy of Imam-e -Zaman, said about him: This Husayn ibn Ruh ibn Abu Bakr Nawbakhti is my successor.
He is a reliable and trust-worthy envoy and deputy between you and the Sahibul-Amr (the Master of the Authority) Therefore, in your affairs and important tasks refer to him and trust him. I was given this task; and I have announced it." Shaykh Tuisi (may Allah's mercy be upon him) said about him: "Abu-l-Qasim Husayn ibn Rim was regarded by his friends and opponents as the most learned man among the people. " The integrity of Husayn ibn Ruhs deputy-ship was acknowledged by his opponents too.
Shalmaghani who was one of the pseudo claimants to the deputyship, had to confess his falsity when Imam-e Zaman ordered Husayn ibn Ruh to expose him. He (Shalmaghani) said: "It is not right between me and Allah to say anything in the affair of Husayn ibn Ruh other than the truth.