Imam Reza (A.S.) thoroughly encompassed all sciences and knowledge. The historians and the narrators have unanimously agreed that he was the most knowledge of the people of his time, the most meritorious of them and the most learned of them in the precepts of religion and other sciences such as philosophy and medicine. Talking about the Imam’s abundant knowledge, "Abd al-Salam al-Harawi has said:
"I have never seen a person more knowledgeable than "Ali b. Musa al-Reza. When a religious scholar sees him, he bears witness for him (as being the most knowledgeable) as I do. Al-Mamun gathered for him in assemblies a number of the scholars of religions, the jurists of Islamic law, and theologians. However, he overcame them to the extent that they acknowledged his excellence (over them) and confessed their feebleness before him. I heard him say: "I used to take my place at the theological center (rouda) and the number of the learned scholars in Medina was quite large. Yet when a question over-taxed the mind of one of those scholars, he and the rest would point at me, and they would sent me their queries, and I would answer them all."
Imam Reza(A.S.) was the most learned of the people of his time and was the highest authority in Islamic world; religious scholars and jurists would send to him their questions about Islamic precepts.
Ibrahim b. al-"Abbas has said: "When al-Reza was questioned about a certain thing, he answered it. I have never seen that there is a person more knowledgeable than him. Al-Mamun examined him with questions about all things, and he answered them."
Imam Reza (A.S.) was the most eminent Muslim thinker, so he was able to develop the cultural and scientific life of the Muslims.
Al-Mamun has said: "I think that there is no person on the face of earth more learned than this man (i.e.Imam Reza(A.S.).
His (i.e. Imam Reza’s(A.S.) debates in Khurasan, Basrah, and Kufa give evidence for his being the most knowledgeable on the face of earth. During those debates he was questioned about the most difficult problems and he answered them, so all the religious scholars of his time yielded to him and acknowledged his excellence over them.
His Knowledge of all Languages
Another example of his being the most knowledge person is that he could speak all languages. Abu Ismail al-Sindi has reported: "When I was in India, I heard that Allah had an Arab proof, so I went out to seek him. I was guided to al-Reza (peace be on him), and I went to him. I could not speak Arabic. I greeted him in Sindhi, and he greeted me in my own language. I asked him in Sindhi, and he answered me in it. I said to him: "I have heard that Allah has an Arab argument, and I have gone out to seek him. He, peace be on him, said to me: "It is I; ask (me) about whatever you desire." I asked him about my questions, and he (peace be on him) answered them in my own language."
Abu` al-Salt al-Hurawi has said: "Al-Reza`, peace be on him, spoke to people in their own languages. I asked him about this (quality), and he replied: "O Abu al-Salt, I am Allah’s proof over His creatures. Allah does not appoint over a people a proof who does not speak their own language. Have you not heard the words of the Commander of the faithful: "We have been given sound judgment. Is this not his knowledge of languages?"
Ya`sir al-Kha`dim (the retainer) has narrated: "Abu al-Hasan (al-Reza`), peace be on him, had in his house Byzantines and Slavs. He was close to them. He heard them speak in Slavic and Romanian, saying: "We are visited in our homeland every year, but we are not visited here." In the following morning he (al-Rida`) sent someone to visit them."
Shaykh Mohammed b. al-Hasan has composed a poem concerning this quality, saying:
And his knowledge of all languages is the clearest miracle and sign.
The Imam uses Supplication as Weapon
Yet another quality of the Imam’s spiritual life is that he practiced supplication as a weapon through praying to Allah and referring to Him in all his affairs, for he found in it (supplication) a spiritual enjoyment which none of the enjoyments of life equaled it. We will mention his statements concerning the importance of supplication before we present some of his supplications.
Supplication is the Weapon of the Prophets
The Imam urged his companions to supplicate Allah and said to them: "Adhere to the weapon of the prophets!"
"What is the weapon of the prophets?" he was asked.
"Supplication," he replied.
Imam Reza(A.S.) advised his companions to conceal supplication, and that man should supplicate his Lord secretly, that none may know of him. He, peace be on him, has said:
"A servant’s secret supplication equals seventy open supplications."
His Kindness to Slaves
Imam Reza (A.S.) did a lot of good and kindness for the slaves. "Abd Allah b. al-Salt reported on the authority of a man from the people of Balakh, who said: "I was with Imam Reza(A.S.) during his journey to Khurasan. One day he called for food and gathered his black and non-black retainers around it. Hence I asked him: "May I be you ransom, could you please isolate food for these (retainers)? As a result, he blamed me for this and said: "The Lord, the Blessed and Exalted, is One, the mother is one, and reward will be according to deeds."
Surely, the Ima`ms of the Household (of the Prophet), peace be on them, behaved in such a manner in order to abolish color discrimination among men and to show that they were in one mosque, and that nothing discriminated one person from another except reverential fear and good deeds.
His Entertaining Guests
The Imam Reza (A.S.),entertained guests, bestowed liberally upon them, and he himself served them. One day a person stopped at him and he spoke to him at night. When the lamp changed, the guest hurried to set it right, but the Imam went ahead of him and he himself set it right and said to his guest: "We are the people who do not employ their guests."
His Releasing Slaves
The most lovable thing to Imam Reza (A.S.) was releasing slaves and freeing them from slavery. The narrators have said: "He (Imam Reza (as.) released one thousand slaves."