He inherited the knowledge of his grandfather, the Messenger of God (PBUH), and thus became its pioneering source that quenched the thirst for knowledge. History narrates many of his scientific positions and intellectual discourses in which he triumphed over the opponents of the divine message and excelled in various branches of knowledge that provided knowledge seekers and thinkers of the time.

Imam Musa al-Kazim (a.s.) is reported to have said to his children many times: "Your brother Ali ibn Musa is the learned scholar of the family of Muhammad (s.a.w.s.), so you can ask him about your religion. Memorize what he tells you, because I have heard my father Ja'far ibn Muhammad say more than once: The scholar of the family of Muhammad is in your loins, I wish I could meet him."

Ibrahim ibn Abbas Sawli is quoted as saying: "I never saw Imam Reza (a.s.) not have an answer to a question that was asked of him, and I did not see his contemporary more knowledgeable than him. Al-Ma'mun tested him by asking him almost everything and always gave him an answer, and his answer and model were always taken from the Holy Quran."