Do not be skeptical of anyone and do not accept whatever you hear without first observing it. It has been mentioned in the holy Qur'an that: you cannot say anything unless you have seen it. Imam Ali (peace be upon him) says: do not talk about the things you are not certain about, Imam Ali ( peace be upon him) not only forbade us not to talk about what you are not certain but also says not to talk about what you already know.
source : erfan.ir
