Ibn Khaldun also states that “ When imprisoned with his mother in the house, he entered a sort of well or pit in the house that his family occupies at Samarrah, Iraq, and there he disappeared, but he is to come forth at the end of the age to fill the earth with justice”.
Allama Jalaluddin Suyuti quotes in his book Jalalul- Oyun Vol.6 page 50. “ The Hour shall not come till Al-Mahdi takes charge on earth on my behalf,” said the Messenger of God. Allama Suytu also quotes Imam Ahmed ibn Hanbal that famous companion Abu Said Khadhri quoting the Messenger of God saying, “I bring you glad tidings of al-Mahdi, God shall send him to my nation, in a time different from your own, and after a series of earthquakes, and he shall fill the earth with justice and equity as it was filled with injustice and oppression.
He shall distribute the wealth equitably among the inhabitants of the earth. In the manual in which he sets forth the many duties and privileges of pilgrims, Majlisi has given an accepted form for a short letter in Arabic, which anyone can write, and sent to his Imam of the age.
It may be placed on the tomb of any of the Imams, or it may be fastened and sealed, and covered with clean earth and cast into the sea or river or a deep well. In any case it will reach the Hidden Imam and he will give his personal attention.
There is a famous saying of Imam Husayn (as) about the twelfth Imam. “The Ninth of my descendants is the Imam who will rise with the Truth. God will grant life to earth through him after its death. The true faith will supersede all religions through him.
His absence shall be lengthy during which many people will go astray. Only a few will remain on the Right Path. They shall suffer pains, people will put pressure on them, saying,” let us know when this promise of the Return of the Mahdi is fulfilled”. Those who will bear the pains and denials patiently will get the same rewards as those who accompanied the Prophet during his expeditions for Jihad.”
Imam Zainul Abedeen (as) has said, “ Of us one will be born whose birth will remain secret so much so that the people will say that he was not born at all.”
Imam Muhammad al Baqir (as) is quoted by Kulaini in Al-Kafi, “ Nine Imams after Husayn are destined, the last of them will be al-Qaim.”
Imam Jafar al-Sadiq (as) is quoted in Ilal al-shara’i saying, “ The fifth of the descendants of my son Musa will be the Qa’im a descendant of the Prophet (S).
Imam Musa ibn Ja’far (as) was asked once, “ Are the Qa’im with the truth?” The Imam replied, “ I also rise truthfully, but the real Qa’im is he who will remove the enemies of God from earth and will fill it with justice. He shall be my fifth descendant. His absence will be lengthy during which multitudes will turn away from the faith while only a few will uphold it”.