"The two feet of the Son of Adam will not move from near his Lord on the Day of Judgement until he is asked about five (matters): about his life - how he spent it; about his youth - how he took care of it; about his wealth - how he earned it and where he spent it; and about that which he acted upon from the knowledge he acquired"

(al-Tirmidhi) [src: p9, The Broken Chain (Ltd Edition), Aftab Ahmad Malik]

 "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]