Because Ibrahim (a.
Because Ibrahim (a.s.) had prayed to Allah, the Mighty and the High that among the latters He should appoint for them a truthful speaker. Therefore the Almighty Allah made Ali the truthful tongue for Ibrahim and Yaqoob (a.s.). Thus Ali (a.s.) informed that the Qaim shall be his eleventh descendant and with the same attestation it is that Mahdi who would fill the earth with justice and equity just as it would have been fraught with injustice and oppression.
And also that there shall be an occultation for him and that the people shall be confused about him, due to which many groups would go astray and many shall be guided.
And this will indeed come to pass just as he has put on the garb of creation.” And he (Ali) has mentioned in the tradition of Kumayl Ibne Ziyad Nakhai: Indeed the earth shall remain established through a Divine Proof who shall either be apparent and well-known or concealed and hidden so that the proofs of Allah and His clear evidences do not become invalid.
I have quoted both the narrations with the chain of narrators in this book in the chapter wherein are mentioned reports of Amirul Momineen (a.s.) regarding the occurrence of occultation. And these two reports are repeated here because it was needed to be quoted in the incident of Prophet Ibrahim (a.s.). And there was another occultation for Prophet Ibrahim (a.s.) in which he undertook journey to other parts for the purpose of religious propagation.
2 - Narrated to us my father; and Muhammad bin Hasan - may Allah be pleased with them - they said: Narrated to us Saad bin Abdullah; and Abdullah bin Ja’far al-Himyari, all of them from Ahmad Muhammad bin Isa from Hasan bin Mahboob from Malik bin Atiya from Abi Hamza Thumali from Abi Ja’far (a.s.) that he said: “One day Ibrahim (a.s.) set out for a walk to derive some lessons from the creatures of Allah. Wandering through the town he reached wilderness and saw a man standing up in prayers.
His voice was reaching the sky and his dress was made of hair. Ibrahim (a.s.) stood there in amazement and watched him pray. Then he sat down waiting for him to conclude the prayers. A long time passed. At last Ibrahim (a.s.) nudged him with his hand saying that he had a request from him and that he should shorten his prayers. The person concluded the prayers and turned towards Ibrahim (a.s.).