( Hadíth de Ibn-i Abbas rapporté par Sa’id ibn-i Jabir dans la tradition chiite)
"My successors after Me are God’s proofs for the people of the earth. They are twelve. First one of them my brother and last of them will be my child. They asked : O Apostle of God ! Who is your brother ? He said Ali-ibn Abu Talib. They asked who is your child ? He said : He is Mahdi who will fill the earth with justice, even if it is full of injustice and wretchedness. I swear to God Who made Me His Messenger even if one day is left from the age of the world, God will lenghten that day to the extent that My child Mahdi will become manifest. Then Issa (Maseeh), the Spirit of God descends (the return of Christ) from heaven and pray behind Him". 

(Hadíth de Ibn Abbas dans le livre de tradition sunnite « Al Araf’ul Vardi fi Akhbaar al-Mahdi »)
 "The Messenger of God said : Al Mahdi is from My Household (he will arise from Muhammad’s family line). He will arise as the Vicegerent of God (kalifa-tullah) and afterward He will relegate His Rulership to Issa bin Maryam".