Among the Shia Imams, four have found more opportunity to spread the truths of religion: Imam Ali (AS), Imam Muhammad Baqer (AS), Imam Ja‘far Sadiq (AS), and Imam Reza (AS). Although all the Imams have made different efforts in this important matter, the conditions for these four Imams were more appropriate in the religious and ideological affairs than others.
Imam Reza’s fields of knowledge are the issues that distinguish him personally from others. Knowledge of Imam in the fields of theology, religions, and Revealed Scriptures, Quranic sciences and teachings, Kalam (theology) discussions, medical and healthcare affairs, jurisprudential principles discourses, jurisprudence and so on, all indicate the extent of the knowledge of the Imam. Imams, based on the many narratives that are related by the religious figures, are inheritors of the knowledge of the Prophet (pbuh).
The Imam, grew up using his divine knowledge and insight of his noble father, Imam Musa b. Ja'far (AS), and although he was only twenty years old, he answered questions of the people in the Prophet's Mosque. The knowledge of the Eighth Imam was so evident that he was called by his noble father, “The learned of the Prophet’s household”.
In the debate sessions, he answered the doubts raised by the figures of religions or Islamic scholars carefully, and presented novel and rational explanations.
Ali b. Muhammad b. Jahm, who himself was Nasebi and one of the enemies of the Ahl al-Bayt, admittedly says: “I was in the assembly of Ma’mun, where Ali b. Musa al-Reza was also present. Ma’mun was asking the Imam about the accounts regarding the non-infallibility of the Prophets, and he answered each one.”
Others, such as Abu Abdullah Hakim Neishabouri, the Shafi‘i traditionist and jurisprudent, Ibn Athir, another Shafi‘i traditionist and jurisprudent, and Ali b. Jahm Nasebi, in their works admitted the countless virtues of Imam Reza (AS), and titles such as Sultan of Awliya (friends of Allah), the proof of the pious, the inheritor of the knowledge of the Prophets, the keeper of the secrets of God, friend of God, God’s chosen one, the beloved of the Prophet of God, aide to the people, wiper of sadness, the king of those brought near to God on the Day of Judgment, al-Imam Abu al-Hassan Ali b. Musa al-Reza, May blessings of God be upon him and the Prophet of Allah … were used for His Holiness.
Amid other traits of Imam Reza, was his familiarity with the world's popular languages. Aba Salt Hiravi says: “Imam Reza spoke to people in their own languages, and I swear by God, he was the most eloquent of people and most knowledgeable of them to any language and accent.”
Aba Salt says: “One day I told him: I wonder how you know all these languages, with all their discrepancies?” The Imam replied: “O’ Aba Salt! I am the authority of God to people, and He does not convey authority to anyone who does not know the language of the people.”