Imam Mahdi, peace be upon him, is the Imam of all Muslims and does not belong to a particular madhhab, but some Islamic madhhabs may have more knowledge about him. In fact, his relationship to Muslims is like that of Amir al-Mu’minin Ali ibn Abi Talib, peace be upon him, to them; all of them accept him as a Caliph, but some of them consider him as the fourth Caliph and some of them as the first Caliph. But there are less disagreements among them about Imam Mahdi, peace be upon him; because they all consider him to be the twelfth Caliph and appointed by God and His Prophet. They only disagree about the name of his father and the time of his birth, and this disagreement does not harm the necessity of preparing the ground for his advent; because the necessity of preparing the ground for his advent does not stem from the name of his father or the time of his birth, but from the necessity of his advent as the Caliph of God and His Prophet, whether the name of his father is Abdullah or Hasan, and whether he was born before or will be born later.