"The Shi'ite Muslims celebrate every 13h of Rajab as Yaum-i Ali, the birth anniversary of Ali bin Abu Talib. The birth of Ali in the sanctuary of Kaba denotes a herald of the divine guidance to be continued after the Prophet, who had said, "I am the Lord of revelation (tanzil) and Ali is the Lord of tawil (interpretation)." It implies that the inner (batin) aspects of the Koran will be imparted by Ali and his descendants in every age till the day of judgment.
The first House of God was rebuilt and renovated at the command of God by Abraham with his son Ismael. The Koran says: "And remember when Abraham raised the foundation of the House with Ismael (praying) Our Lord accept (this service) from us" (2:127) and "And We enjoined Abraham and Ismael, saying, Purify My House for those who visit it and those who abide in it for devotion and those who bow down and those who prostrate themselves" (2:125).
These verses clearly depict the purpose of the Kaba that it was to be a place of worship and that it was pure and sacred. Kaba is also called al-Bayt al-Haram in the Koran (5:97) and al-Muharram (14:37), which carries the same significance as al-Haram, both meaning originally al-mamnu min-hu or that which is forbidden. Means it is a place whereof the sanctity must not be violated. When Mary became pregnant, and the time of her delivery approached, she was commanded to leave this holy House for it was a House for prayers, not a place for the delivery of children. Thus, she left the holy House and went to the wilderness where she gave birth to Jesus. But when Fatima bint Asad, the mother of Ali, felt labor pains within the precincts of the Kaba, a fissure appeared in the wall, and she went in, where Ali was born. Ali has thus had the unique honour to be born in the House of God. This unparalleled honour had endowed Ali with a halo of sanctity that has become the subject of many legends.
It was in the month of Rajab that Arabs from the length and breadth of their country used to come to Mecca for pilgrimage. Fatima bint Asad, an embodiment of chastity and piety, was among those pilgrims. On Friday, the 13th Rajab in the 28th years of A'am al-Fil, or 600 A.D., Fatima bint Asad, entered Kaba to perform pilgrimage. While circumambulating the Kaba, she felt the pangs of childbirth. She retired to a secluded place in the precincts of the Kaba, and there Ali was born. It is related that she felt weighed down by intense pain when Ali was due to be born. She knelt to pray, and when she raised her head from her prostration, the wall of the Kaba split as if a miracle, to admit her within, and the portion of the wall returned to its normal position after she had lodged herself in the cavity. When the lovers of Ali go for hajj and umra, they always remember his birth in the Kaba and whilst making the tawaf (the ritual circling of the Kaba), they feel proud and happy that Ali's name is linked with the House of God, and at every circuit they look towards the wall. This particular place is known as mustajar.
A hundred years later, Imam Zayn al-Abidin met an Arab woman at Najaf who told him that her grandmother had helped Fatima on the occasion of Ali's birth. She narrated that according to the account of her grandmother, the child was beautiful; a smile played on his lips; he did not cry like other children; and his birth did not cause any pain to his mother.
Fatima bint Asad stayed inside Kaba for three long days after Ali's birth, and as the fourth day approached, with awe, the wonder struck crowds surrounded the Kaba and to their surprise, she emerged radiant from the sacred premises, cheerfully holding her new-born babe in her arms. Yet another surprise awaited them that the Prophet was waiting to receive her and her newly born child, and the first face the little Ali saw in this world was the smiling face of the Prophet of Islam. Ali accepted no other food than the moisture of the Prophet's tongue, which he sucked for several days after his birth. The Prophet fondled him in his lap in his infancy, and chewed his food and fed Ali on it. Ali has been described as having been found like a priceless pearl in the shell of the Kaba, or a sword in the sheath of God's House, or as a lamp found in God's abode shedding Light all around.
The sanctified birth of Ali in the Kaba is unique, for this is the only known occasion on which a child was born within the precincts of the holy place ever since its foundation thousands of years ago. "The thirteenth of Rajab" says a Shi'a writer, "marks the birth of a most precious pearl in the courtyard of the Kaba, glowing in its full self-illumination. It was a portion of the very divine light of God that appeared in the human shape and form, and commenced to shine on the highest of the human stages of dignity and reverence" (cf. Ali The Super Man, Lahore, 1964, p. 19).
Masudi writes in Muruj adh-Dhahab (2:76) that, "One of the greatest distinctions that Ali enjoyed was that he was born in the House of God." Imam Hakim in his Mustadrak (3:483) and Ibn Sabbagh Maliki in his Fusulul Muhimma (p. 14) write that, "No one before Ali was born in the Ka'ba. This was a distinction given to Ali in order to enhance his honour, rank and dignity.
Mahmud Saeed al-Tantawi, of the Supreme Council of Islamic Affairs, Arab Republic of Egypt, writes in his book, Min Fada-il al-Ashrat al-Mubashireen bil Janna (Cairo, 1976, p. 186) that, "May God have mercy upon Ali ibn Abi Talib. He was born in the Kaba. He witnessed the rise of Islam; he witnessed the mission of the Prophet, and he was a witness of the Koranic revelation. He immediately accepted Islam even though he was still a child, and he fought all his life so that the word of God would be supreme." For further, vide Muhammad ibn Talha al-Shaf'i in Matalib-us-Saul (p. 11), Umari in Sharh Ainia (p.15), Halabi in Sira (1:165), Sibt ibn Jawzi in Tadhkera Khawasil Ummah (p. 7), Muhammad bin Yousuf Shaf'i in Kifayet al-Talib (p. 261), Shablanji in Nurul Absar (p. 76), Ibn Zahra in Ghiyathul Ikhtisar (p. 97), Edvi in Nafhatul Qudsia (p. 41), etc.