It was narrated that Abu `Uthman an-Nahdi said:
l was sitting beneath the minbar of `Umar (رضي الله عنه) when he was addressing the people, and he said in his khutbah:I heard the Messenger of Allah (ﷺ) say: “What I fear the most for this ummah is every knowledgeable hypocrite with a smooth tongue.”