Peace be on you, O the decisive argument of Allah on His earth! Peace be on you,
O the ultimate link of Allah with the mankind! Peace be on you, O the truth and enlightenment
of Allah whom the guided on the Right Path follow and imitate, and who gives heart, joy and
confidence to the faithfuls! Peace be on you, O the just, pure and refined
rendered formidable! Peace be on you, O the "Wali" (beloved favourite of Allah, a friend, a helper)
who always gives sincere advice! Peace be on you, O the means and medium of
liberation and assurance! Peace be on you, O the spring and essence of life!
Peace be on you. Blessings of Allah be on you and on your pure and pious family.
Peace be on you. May Allah fulfil, at once, in advance, the promise He made
with you-to shower mercy and make distinctly visible (your) leadership.
Peace be on you, O Loving Protector! I am your friend and follower, well aware of your priority and
ultimate purpose. I come near Allah, the Highest High, through you and your family.
I look forward to be there when you come, at your disposal for making known the truth.
I request Allah to send blessings on Muhammad and on the children of
Muhammad, and make room for me amid those who have fixed the look upon you,
who shall comply with your instructions and help you against your enemies,
and let me be present before you along with all your friends. O loving protector!
O the Man of the moment! Blessings of Allah be on you and on your family.
Today is Friday, a day you are expected to come; the faithfuls will be free of
cares and troubles when you shall arrive, and with one strike shall put
an end to the intrigues of the infidels. I, O the Loving friend, in these
hours, seek your hospitality and friendship. You, O my Loving friend,
are kind and generous, a true son of the kind and generous forefathers,
always inclined by nature to be hospitable and friendly. So give me a warm welcome
and make friends with me. Blessings of Allah be on you and on your family.

  The promised Mahdi, who is usually mentioned by his title of Imam-i 'Asr (the Imam of the "Period") and Sahib al-Zaman (the Lord of the Age),is the son of the eleventh Imam. His name is the same as that of the Holy Prophet. He was born in Samarrah in 256/868 and until 260/872 when his father was martyred, lived under his father's care and tutelage. He was hidden from public view and only a few of the elite among the Shi'ah were able to meet him.
After the martyrdom of his father he became Imam and by Divine Command went into occultation (ghaybat). Thereafter he appeared only to his deputies (na'ib) and even then only in exceptional circumstances. 

  The Imam chose as a special deputy for a time Uthman ibn Sa'id Umari, one of the companions of his father and grandfather who was his confidant and trusted friend. Through his deputy the Imam would answer the demands and questions of the Shi'ah. After Uthman ibn Sa'id, his son Muhammad ibn Uthman Umari was appointed the deputy of the Imam. After the death of Muhammad ibn Uthman, Abu'l Qasim Husayn ibn Ruh Nawbakhti was the special deputy, and after his death Ali ibn Muhammad Simmari was chosen for this task.
A few days before the death of Ali ibn Muhammad Simmari in 329/939 an order was issued by the Imam stating that in six days Ali ibn Muhammad Simmari would die.Henceforth the special deputation of the Imam would come to an end and the major occultation (ghaybat-i kubra) would begin and would continue until the day God grants permission to the Imam to manifest himself.

  The occultation of the twelfth Imam is, therefore, divided into two parts: the first, the minor occultation (ghaybat-i sughra) which began in 260/872 and ended in 329/939, lasting about seventy years; the second, the major occultation which commenced in 329/939 and will continue as long as God wills it. In a hadith upon whose authenticity everyone agrees, the Holy Prophet has said, "If there were to remain in the life of the world but one day, God would prolong that day until He sends in it a man from my community and my household. His name will be the same as my name. He will fill the earth with equity and justice as it was filled with oppression and tyranny."