Translation of an article, composed off of a talk Ayatullah Shubeyri Zanjani gave. The letter that is being referred to in the article can be read here.
Chaotic political circumstances during the time of Imam Hasan al-Askari (as) and the strangulation of his activities by the ruler of the time, was a reason that forced Imam Hasan al-Askari (as) to lead the Shi’ite community through means of delegations and through means of writing letters. This is because the Imam (as) did not have an easy way to stay connected with the community, in order for them to be able to ask their questions him directly and thus be able to answer them. Due to this reason, the Imam (as) had sent various letters to the Shi’as of the time. For example, the letter sent to Ishaq bin Ismaeel al-Nishaburi, the letter to the residents of Qom, and his (as) letter to Ali bin Babawayh.
The letter that was sent to Ali bin Babawayh has some valuable points, and important moral advises. We will glance over some of these points.
Ali bin Hussain bin Babawayh (father of Sheikh Saduq) was one of the most outstanding scholars and jurists of his time. He ran a small store in the bazaar and made his livelihood through business and commerce, while maintaining piety and chastity. Likewise, he would spend hours at his place, teaching and preaching the religion and as well as narrating the traditions of the Ahlul Bayt (as).
The majesty and position of this great jurist, reached such a peak that Imam Hasan al-Askari (as) referred to him in his letter by different titles, such as “My Sheikh”, “My Trustee”, “My Jurist”. Also, at one point in his life, he had gone past the age of 50 and still had no offspring. Therefore, he wrote a letter to Imam Al-Mahdi (as) and requested him (as) to pray for him so that Allah (swt) would bless him with a righteous child – who would also become a jurist.
Abu Ja’far bin Ali al-Aswad says: I delivered the letter of Ibn Babawayh to Hussain bin Ruh – the third agent of the Imam (as). After three days, he informed me that the Imam (as) has prayed for Ali bin Hussain bin Babwayh and has said:
«انّه سيولد له ولد مبارك ينفع اللَّه به و بعده اولاد»
Allah (swt) will give him a blessed child very soon and through him, He (swt) will deliver good to the people, and after him (Sheikh Saduq), He (swt) will also bless him (Ibn Babwayh) with another son.
In regards to the above point, Sheikh Saduq in one of his books by the name of Kamal al-Deen, additionally says that every time Abu Ja’far bin Ali al-Aswad would see me going to my teachers in order to seek knowledge and scholarship, he would say to me: This love and enthusiasm for knowledge that you possess is not a surprise, because you were born due to the prayer of Imam al-Mahdi (as).
The deceased Allamah Majlisi also considered this as one of the miracles of Imam Al-Mahdi (as) in his valuable book, Bihar al-Anwar.
Some Points from the Letter
1. The esteem, position, knowledge and piety of Ibn Babawayh was at such a degree that the Imam (as) considered him as one of his trustees and recognized him as one of the senior scholars and jurists of the Ahlul Bayt (as). Indeed Ali ibn Hussain al-Qummi is from one of the dignified companions and true followers of the Qur’an and itrat, and is considered one of the pillars of Tashayyu.
2. After praising and thanking Allah (swt), the Imam (as) advises this great jurist to maintain patience, piety and to carry out fulfilling his obligations and as well as to perform the Night Prayers. Apparently, the Imam (as) wished for all Shi’as to know that true leadership is that when man himself grasps on to the obligations ordained by Allah (swt) and acts upon them.
3. The Imam (as) invites Ali bin Hussain to wait for the faraj and informs him that this waiting is one of the greatest acts a Shi’a can perform. However, it must be pointed out that the Imam (as) does not mean just to wait for the reappearance (in the sense that one just sits back), because if that type of waiting by itself was considered worship, everyone is already performing it. In fact, what the Imam (as) meant by “wait”, and the wait which has generally been praised, is the waiting of a man who has found the correct path of the Ahlul Bayt and holds on to it. It is the waiting carried out by the true Shi’ias whose righteous actions are in fact preparing the world for his reappearance.
4. In a part of his letter, the Imam (as) prays for Ali ibn Hussain. He prays that he finds the opportunity to perform acts which are in accordance with the truth and implies that may he receive a righteous offspring. This prayer of the Imam (as) was accepted and Ali bin Hussain did indeed find himself to be a blessed individual who was a safe haven and abode for others. Allah (swt) also granted him a son through the intercession of an Imam (a). A son who was righteous, meritorious and blessed, just like his father who himself was one of the shining stars of Shi’ite scholarship.
Just like his father, he battled against deviations and became a safe haven for the Shi’ite community. There were around three-hundred works written by this great individual, Man La Yahdhuruhul Faqeeh being the most important one. Sheikh Saduq, in accordance to the requirements of his time, compiled works of various kinds. He did not remain heedless of teaching and catering for the needs of the Shi’as. If he wrote on topics pertaining to jurisprudence and Shi’ite theology, he also likewise paid attention to topics pertaining to training oneself and the community in general through improving our akhlaq, and perhaps his books Thawaab al-A’maal and A’qaab al-A’maal are proof of this.
 Bihar al-Anwar, volume 51, pg 335 & 336