The title of a chapter in Usul-e-Kafi reads: "Imamate is a Trust from God which keeps on being transferred from one Imam to another under His command". In this Chapter, Imam Jafar Sadiq is reported to have said: "Imamate is a covenant as regards persons specified by God. Even an Imam has no right to appoint anyone else as the succeeding Imam besides the one nominated by God.’ It is followed by another saying of Imam Jafar Sadiq. It reads: "Do you think that an appointed Imam among us can appoint anyone as his successor? By God! It is not so. It is a covenant from God and His Apostle in favour of specified persons, one after the other, till it reaches the Last Imam, the Absent One." (p. 170).

There are several other narrations of the same import in this chapter.

For every Imam a sealed envelope had been sent down to the Prophet (peace be upon him) containing particular instructions.

In Usul-e-Kafi a very long saying of Imam Jafar Sadiq has been quoted about nomination of Imams by God and particular instructions for them. A gist of it is given below.

"Imam Jafar Sadiq said that Gabriel had brought from the heavens a testament in the shape of a book in a sealed cover. No other thing had bee sent down to the Apostle of God in the form of a sealed packet. It contained sealed envelops for every Imam. The Prophet gave all the envelops to Hazrat Ali who opened only the envelop in his name and read the testament. Likewise, every Imam got his sealed envelope and he read only the letter in his name. The last envelope will be given to the last Imam, Imam Mehdi.". (pp. 171-172).

The narration runs into five to six pages, and, hence, here we have only given a summary of it.

The descent of a mysterious Tablet from the Heavens and nomination of twelve Imams by God.

In Section Al-Hujjah, of Usul-e-Kafi there is a chapter in which narrations are set forth indicating that God had clearly nominated all the twelve Imams, name by name. In one of these narrations an amazing account of the descent from the sky of a green tablet has been given on which the names of the twelve Imams along with their detailed introduction were written in resplendent letters. It, also is a long report, and, therefore, only a gist of it is being given here.

Abu Basir relates that Imam Jafar Sadiq, once, said:

"My father, (Imam Baqar) said to the Companion, Hazrat Jabir bin Abdullah Nasri that he had some business with him; so when would it be convenient for him to meet him in private. Jabir replied that he could come whenever he liked. My father went to him, one day, and asked him to tell him about the tablet he had seen in the hands of his great grandmother, Hazrat Fatima, daughter of the Apostle of God, i.e., what was recorded in it and what she had told him about it. Jabir bin Abdullah said, making God his witness, that (once) he had gone to Hazrat Fatima in the life-time of the Prophet (peace be upon him) to congratulate her on the birth of her son, Husain. She was holding a green tablet in her hand. I thought it was of emerald. On it was written something in letters bright as the sun. I said to her, ‘O daughter of the Apostle of God! My parents may be a sacrifice unto you. Tell me, what is this tablet, and for what it is meant’? she replied, ‘God has sent this tablet. On it are recorded the names of my father and my husband (Ali), and the names of my two sons (Hasan and Husain), and of all the sons of my rogeny who are to become Wasi. To convey the glad tidings to me, my father has given the tablet to me. Jabir continued, ‘Your great grand mother Fatima (may God he pleased with her) gave the tablet to me to have a look at it. I made a copy of it and kept it with me. My father enquired of Jabir whether he could show the copy to him. Jabir replied in the affirmative. My father went with Jabir’s to his house. He brought out a piece of parchment. My father asked Jabir to look at the parchment and he (my father) would recite what was written in it from memory. My father, thus, told exactly what Jabir had written. Jabir bin Abdullah, then, swore again by God and said that it was exactly what was written in the original tablet." (page 343).

The text of the tablet, then, is given in another tradition which takes a full page of Usul-e-Kafi, and, in it, the names of from Hazrat Ali to the twelfth Imam are mentioned. (p. 344).

During the Caliphate of Hazrat Abu Bakr, Hazrat Ali one day held his arm and took him to meet the Prophet (peace be upon him). The holy Prophet directed Hazrat Abu Bakr to believe in the Imamate of Hazrat Ali and eleven other Imams of his progeny and express penitence for what he had done in the matter of caliphate.

Another strange, story on page 348, of Usul-e-Kafi has it that, one day, Hazrat Ali said to Abu Bakr that the Quran tells:

"And do not regard those slain in the cause of God as dead. Nay, alive are they with their Lord, well provided with sustenance". (III. 169).

Hazrat Ali, then, said, "I swear that the Apostle of God (Peace be upon him and his dependents) had died as a martyr in the cause of God. By God, he will appear before you. So, believe that it is no one else but him when he appears for Satan can not feign his appearance in anybody’s thought (or imagination). Then, Hazrat Ali held the hand of Abu Bakr and showed him the Prophet of God who said, ‘O Abu Bakr, place faith in Ali and on the eleven Imams in his progeny. All of them will be like me except for Prophethood, and, O Abu Bakr, be penitent before God that you have usurped the Caliphate for you had no right to it?’ After saying this, the Prophet went away, and was not seen again".