Imam Al-Ridha [as] said:
* The friend of any individual is his mind, and his enemy is his ignorance.
* A man who takes pain and labors for himself and his children is like some one who fights a holy war (Jihad).
* Keep yourself clean, since cleanliness is the manner of Prophets.
* Worst of the people is the one, whose existence is of no use to the people.
* The one who commits dishonesty with a Muslim is not one of us.
* The character of faith is achieved only when the believer enjoys three qualities from his Lord, the Prophet (peace be upon him and his family), and the leader –the Imam- (peace be upon him). The quality that he should learn from his Lord is the concealment of secrets, the quality that he should learn from the Prophet (peace be upon him and his family) is the courteous behavior, and the quality that he should learn from the leader (peace be upon him) is steadfastness against poverty and distress.
from: Tuhuf al Uqool
A discussion with other religion scholars
One of the days Mamoon decided to invite the scholars from different sects of the world and he brought Imam Reza (A.S.) to the assembly. He thought he might be able to get the Imam (A.S.) invalidated and un-credential from the knowledge point of view, thus finish his influence.
Therefore, he ordered his minister Fazal bin Sahal to invite all the scholars and wise men to hold a discussion with Imam (A.S.). And he did it. When the assembly had been arranged he informed Mamoon that all are present. Mamoon summoned Imam Reza (A.S.) inviting him to attend the assembly.
Hassan Naufali says, before leaving the house to attend that aggregation facing myself Imam (A.S.) said, “I know the aim and objective of Mamoon in this work.” But I know the time when he will repent upon his work that is; when you see that I talk to the Christians from their own Book and talk to the Jews from Torah and with fire worshipers in Persian language. When all of them are defeated Mamoon will become aware that he is not fit for that past. He will repent upon this work of his. What Imam (A.S.) had said exactly and accurately took place. When Imam (A.S.) arrived the assembly, all of them got up from their seats to honor him. He seated himself beside Mamoon. Mamoon addressing “Jasaleeq,” the great Christian scholar said, “Ask him what you feel like.” “Jasaleeq” said, “What is your opinion about Christ Essa (A.S.).” Imam (A.S.) said, “We believe he was the Prophet of God” Jasaleeq again asked, “What proof do you have about your own Prophet’s Prophet-hood.” Imam (A.S.) said, “Have you not read it the Bible that Yohana narrates the saying of Christ (A.S.) that, “A Prophet will come following me, who will be the accomplisher of the constitution of the other Prophets.”
He said, “Yes, but he did not name him as to who and where he will be.” Imam (A.S.) said, “Do you wish that I may read out to you from the Bible?”
He said, “Read it.” Imam (A.S.) recited the third chapter up to the place where Christ (A.S.) said, “I will proceed towards God and “Barklita” i.e. “Mohammad (P.B.U.H.)” will come towards you and he will break and dismantle the infidelism.
Jasaleeq became silent and did not utter a word.
Then Imam (A.S.) facing “Raasul Jalout” the chief scholar of the Jewish religion said, “What is the proof and argument that you have about the Prophet-hood of Moses (A.S.)?”
He replied “Moses (A.S.) had miracles such as turning the club into a serpent, splitting the river Nile and passing through it and a light shone from his hand.”
Hazrat Imam (A.S.) said, “Why did you not believe in the Prophet-hood of Essa the Christ (A.S.)?”
He said, “They say Christ (A.S.) made the dead men alive and cured the skin diseases but we have not seen these to have faith and belief in it?”
Imam (A.S.) said, “Then why do you believe in the Prophets before him? Similarly in Moses himself have you seen the miracles of Moses?”
He replied, “The way it has been narrated to us he has said, such things which other have not and brought such things which have no previous record.”
Imam (A.S.) said, “From which source did you come to know that he brought these words.”
He replied, “Through the history and those who heard those words from him.”
Imam (A.S.) said, “Others too seek refuge in history and so how do you want to invite them to your creed?”
Raasul Jalout kept calm and quiet and did not utter a word.
Then Imam (A.S.) turned to Imran the chief of the Star worshipers and said, you too ask me what you wish. Imran questioned him regarding a few topics about God, the philosophy of creation and got his answers and embraced Islam at the hand of Imam (A.S.). The assembly finalized and came to an end to the benefit of Imam (A.S.) and Mamoon did not expect and foresee such a thing to happen. He turned and twisted like a snake bitten person and rebuked and scolded himself for organizing such an aggregation.