Imam Muhammad ibn `Ali ibn al-Husayn had the title of Baqir, that is to say ‘One who analyzes’. He was called Baqir al-`Ulum meaning one who analyzes the knowledge. A Christian, in a mockery and ironic way playing on words of Baqir, misinterpreted to Baqara called him, “You are Baqara (cow)!” Without expressing any annoyance or anger, the Imam replied calmly, “No, I am not baqara but I am Baqir.” The Christian said, “You are the son of a lady-cook.” The Imam said in reply, “It was her job, which is not considered an insult or disgrace to her personality.” The Christian said, “Your mother was black, immodest and had an abusive tongue.” The Imam said, “If whatever you attribute to my mother is true, I pray Allah to forgive her and absolve her sins, and if it is a lie, may Allah forgive you for your lies and slander.”
Observing such a clemency from a person who had the authority to submit a non-Muslim to different persecutions was sufficient to provoke a revolution in the soul of the Christian and invite him towards Islam. Later on, he embraced Islam. ( Al-Manaqib: 207/4.)