The Just Leader of Humanity 6
These three propositions make it necessary to conclude that the existence of the Imam Mahdi is beyond any doubt, and that since he does not live a visible existence, he must be in occultation.
The Short and Complete Occultation
Dr. Jalali: What is the meaning of 'short' and 'complete' occultation?
Mr. Hoshyar: It means that the twelfth Imam (peace be upon him) remained concealed from the public at two different times. The first period extends from the time of his birth in 255 or 256 AH/868 or 869 CE or from the time of his father, Imam Hasan 'Askari's death in 260 AH/873 CE, to the year 329 AH/940 CE. During this time, although he lived an invisible existence as far as the public was concerned, he was not completely cut off from them. Rather, he maintained regular contact with his followers through his deputies, who were able to reach him and present to him their needs and inquiries. The existence of the Imam during this period that lasted some 74 or 69 years is known as ghaybat-i sughra.
The second period extends from the year 329/940, with the termination of the deputyship of his prominent and trustworthy associates, to the time when he will emerge from the state of the occultation to lead humanity to establish the rule of justice and equity on earth. This period of occultation is known as ghaybat-i kubra.
Both the Prophet and the Imams (peace be upon them) had informed people about the two forms of occultation for the Mahdi. Thus, for instance, Ishaq b. 'Ammar relates a hadith he heard from Imam Sadiq:
The Qa'im will have two forms of occultation: one long and the other short. During the first occultation his special followers will know his whereabouts; during the second occultation, except for a few very special followers of his in his religion, no one will have any information about his whereabouts.
In another tradition Imam Sadiq said:
The one who is entrusted with the command (sahib al-'amr) will have two forms of occultation. One of them will be so long that a group of the people will say that he has died; others will say he has been killed; still others will say he has disappeared. Very few will remain who will still have faith in his existence, and will continue to be steadfast. At this time no one will have any information about his whereabouts except his very few followers.
The Short Occultation and the Contacts with the Shi'a