The second special deputy of Imam Mahdi was Abu Ja‘far Muhammad ibn ‘Uthman ibn Sa‘id ‘Amri. After his father’s death, he succeeded him and was appointed as the representative and deputy of Imam Mahdi.
Among his other services was struggling against and defeating the false pretenders to the deputyship. Muhammad ibn ‘Uthman was the special deputy of Imam Mahdi for about 40 years, and false claims to deputyship were rampant then. Under the guidance of Imam Mahdi and his letters, Muhammad ibn ‘Uthman could struggle against and defeat them.
Like other deputies, his other works included addressing people’s problems, answering their legal problems, and delivering people’s letters to the 12th Imam and getting his responses to them.
In his lifetime, he offered many services to Shi‘ism, such as writing books on Islamic Jurisprudence, and gathering the material of his books from the teachings of Imam Hasan ‘Askari, Imam Mahdi, and his own father, whose source was these holy Imams, too. Based on his will, this book was handed on to the third deputy of the Imam, Husayn ibn Ruh Nowbakhti.