I never saw that Ar-Ridha’ (a.s.) be asked a question and he did not know the answer. I have never seen anyone more knowledgeable than him (a.s.) from the beginning of history up until his time. Al-Ma’mun constantly tested him (a.s.) by questioning and he (a.s.) always responded. He cited all his words, answers and similitude from the Qur’an. He read the Qur’an completely once every three days. He (a.s.) used to say, “I can read all the way through the Qur’an even faster if I wish. But in the way I read it now, I ponder over the meanings and on the occasions in which the verses have been revealed, and the time of their revelation. That is why it takes three whole days and nights.” One of his famous sayings is, “Minor sins are the road to major sins. Whoever does not fear God when he commits a minor sin will not fear Him when committing a major sin. Even if God had not admonished the people regarding Heaven and Hell, it was obligatory for the people to obey Him and stay away from disobeying Him. This is due to the nobility and kindness that He has bestowed upon them and having brought them into existence from being non-existent which they did not deserve!”