"Truly, Allah does not remove Sacred Knowledge by taking it out of servants, but rather by taking back the souls of Islamic scholars [in death], until, when He has not left a single scholar, the people take the ignorant as leaders, who are asked for and who give Islamic legal opinion without knowledge, misguided and misguiding"
(Sahih Bukhari - Fath al-Bari, 1.194, hadith 100) [src: suhba.org]