In the Name of Allaah,the Most Gracious,the Most Merciful
Shaykh Saleh al-Fowzan (حفظه الله تعالى) stated:
The individuals who ascribe themselves to (giving) da’wah,it is mandatory that they be investigated:
Where did they study?
Where did they take knowledge from?
Where were they reared?
What are their beliefs?
Their action must be investigated, their effects upon the people, along with what good they have brought about.
What rectification has their actions produced?
Their affairs must be investigated before (the people) are misled by their statements and what is apparent from them. This investigation is mandatory, especially during the present time in which the callers to fitnah are many.
Source: Al Ejabaat al Muhimah fil Mashakil al Mulimah, page. 34|Translation by Ustaadh Mustafa George Deberry (hafidhahullaah) of www.knowledgeofislamblog.wordpress.com