Imam Mahdi (PBUH) (Arabic: امام مهدي) is the 12th and last Shia's Imam from the descendants of prophet(messenger of God)1Mohammad (sa)2.
It was narrated in all holy books (Torah, Bible, Quran) that he will return with Prophet Jesus (pbuh) to save the world and spread the justice , put an end to any kind of oppression all over the world and guide the people to righteousness.
Imam Mahdi (Aj) son of Imam Hassan Al-Askari was born in Samarra in 869 AD (15th, Sha'ban, 255 AH) and his mother was lady Narjes.
He was the next Imam after his father, Imam Hassan Al-Askari (As) was martyred by the Abbasid Caliph. His father was the 11th Imam, Imam Hassan Askari (as).
The twelfth Imam, Imam Mahdi (Aj) did not appear in public
from the first day of his life because he is the last Imam and must be protected by God to return and save the world and spread the justice and put an end to any kind of oppression all over the world but the enemies of the Imams and the enemies of God knew him by prophecies, so they tried to kill him so God disappeared him to save him like the Prophet Jesus (pbuh), because their return is God's great promise in all holy religions and holy books.
Therefor about 69 between 74 years people contacted him
through his special representatives to reach him: (Uthman ibn Sa'id, Muhammad ibn Uthman, Hussein ibn Ruh and Ali ibn Muhammad al-Simri). This 69 between 74 year known as the Minor Absence (Ghaybat Al-Soghra), and at the end of that, the major Absence (Ghaybat Al-Kubra) began.
The absence of Imam Mahdi (pbuh) is divided into two parts: the first part, the minor occultation (Ghaybat Sughra) which began in 872 and ended in 939, and lasted about seventy years. Second, the great occultation that began in 939 and will continue as long as God wills.
During the great occultation until the time of his reappearance, no one was his special representative, and there will be no one in the future, and people have a duty to refer to the Qur'an, the hadith of the Ahl al-Bayt, and "Fuqaha" (Jurists), those who are proficient in knowledge of Sharia (Islamic law) and the narration of hadith and specialize in the affairs of religion.
Believing in the advent of the expected Mahdi (pbuh) that the world peace is not limited to Shiite Muslims. Other Islamic groups and even non-Islamic groups such as Jews and Christians and some of the world's great intellectuals believe in the emergence of a great spiritual reformer.
Shiite narrations predict that Imam Mahdi (as) and Jesus (pbuh) will return together to reform the world. For more information, refer to "Secrets of the Bible", "Imam Mahdi (as) in other religions", "Promised in Christianity", "Ahl al-Bayt promised in Gaspel".
Countless hadiths (prophetic words) have been narrated in Sunni and Shiite sources from Prophet Muhammad (PBUH) and his sons (Ahl al-Bayt) about the advent of Imam Mahdi (PBUH) that he is one of the sons of the Prophet (PBUH) and his emergence enables human society to reach true perfection and full realization of spiritual life. In addition, there are several other narrations about the fact that Imam Mahdi (as) is the son of the eleventh grandson of Prophet Mohammad (PBUH), Imam Hassan Askari (as). They have a consensus that after birth and during a long absence, Imam Mahdi (pbuh) will reappear, filling the world with justice that has been ruined by injustice and iniquity.
For example, Imam Reza (pbuh) (the eighth Shiite Imam, a descendant of the Prophet Muhammad (pbuh)) said in a hadith: "The Imam after me is my son Muhammad (Imam Muhammad Javad), and after him his son Ali ( Imam Ali Hadi), and after Ali his son, Hassan (Imam Hassan Askari), and after Hassan his son Hojjat al-Qaim (the risen reason), he is the one that people wait for when he is absent and obey him when he appears. If there is only one day left in the life of the world, Allah (God) extends that day until he is revealed and fills the world with justice as it was filled with lawlessness. But when? As for the news of the hour, my father really told me, he heard it from his father, he heard it from his father, he heard it from his father, he heard it from his father, he heard it from Imam Ali (pbuh), the Holy Prophet was asked, "O Prophet of God, when is Ghaem "(the risen) will appear who is from your family?" he answered: "His case is as unknown as the Day of Judgment. God will reveal it at the right time. It comes to you unawares.”
(Holy Quran, Surah Al-A’raf, verse 187)
Saqr Ibn Abi Dulaf said, “I heard from Imam Javad (9th Imam) who said, ′The Imam after me is my son Ali (Imam Ali Hadi); his command is my command; his word is my word; to obey him is to obey me. The Imam after him is his son, Hassan (Imam Hassan Askari). His command is the command of his father; to obey him is to obey his father.′ after these words the Imam remained silent. I said to him, ′Oh son of the Prophet, who will be the Imam after Hassan? ′ the Imam cried hard, then said, ′Verily after Hassan his son is the awaited Imam who is “Al-Qa’im bi’l-haqq” (He who rise for the Truth).′”
Musa ibn Ja'far al-Baghdadi said, "I heard Imam Hassan al-Askari (as) (the eleventh Shiite Imam) say, 'I see that after me there will be differences about the Imam after me among you.' Whoever accepts the Imams after the Prophet of God but denies my son (Imam Mahdi) is like a person who accepts all the prophets but the Prophet of God (PBUH) denies the Prophet of God. And whoever denies the Prophet of God (pbuh) is like one who has denied all the prophets of God, obedience to our last is like obedience to the first and denial of our last is like denial to the first. But beware, there is indeed an occultation for my son in which all people doubt, except those whom God protects."
There is no doubt that the idea of Imam Mahdi (pbuh) in turn has been projected by several Imams, but this form can only find a specific form about the twelfth person with whom the goal of Imamate is achieved. There is considerable literature about him, both in Persian and in Arabic. The sources of this literature have been collected by Saffar Al-Qomi, the reporter of Imam Hassan Askari (as). Al-Kulani and his followers Al-Nu'mani, 4th / 10th century; Ibn Babawiyyah, who owed his information to a contemporary witness, Hassan ibn Mukhtab; Sheikh Mufid; Muhammad bin Hassan Tusi. The main narratives are collected in volume 13 of the Al-Majlisi’s Encyclopedias.
In Shiite Islam, Imam Mahdi (pbuh) is the "hidden Imam" who has already been born and will one day return with Jesus (pbuh) to fill the world with justice. The Promised Mehdi (pbuh), who is usually referred to in Shiites as "Imam al-Asr" (Imam of "time") and "Sahib al-Zaman" (lord of the age).
In a hadith that Shiites and Sunnis agree on, Muhammad (pbuh) said, "If one day remains in the life of this world, God will prolong that day until a man from my community and my family sends there.His name will be the same as my name. He will fill the earth with justice as he was filled with oppression and tyranny."