When Imam Ali (AS) married the dear daughter of the Prophet (PBUH), Lady Fatimah Zahra (AS), the arch angel Jabrail brought an apple from the heaven for the Prophet (PBUH). The Prophet (PBUH) divided the apple in two halves and gave one half to the married couple. After a while the Prophet (PBUH) told his daughter: Soon you will give birth to a boy and on that occasion, Jabrail will congratulate me.
Before the birth of Imam Hassan (AS), Umm Fazl, a cousin of the Prophet (PBUH) told him: I dreamt last night a part of your holy body is in my house and I am looking after it. The Prophet (PBUH) replied: Soon my daughter will give birth to a boy and you will be nursing him. When the time arrived, the Prophet (PBUH) sent for Asma Bint Amees who was a midwife and Umm Salameh, the midnight of Tuesday 15th day of the holy month of Ramadhan, year 2 AH, Medina was illuminated [1].
In the morning whilst wrapped in a yellow cloth, the new born child was brought to the Prophet (PBUH). The holy Prophet (PBUH) removed the yellow cloth and wrapped the child in a white cloth and then embraced the child. The Prophet (PBUH) placed his tongue into the child’s mouth, kissed his soft and beautiful face, recited Azan in his right ear, recited Iqamah in his left ear and then prayed for the child, saying: Please Allah (SWT), protect me, him and his children from the evils of Satan.
On the seventh day, Jabrail came to the Prophet (PBUH) and congratulated him from Allah (SWT) and presented to him a silk cloth and said: On the divine order name the child, Hassan. The Prophet (PBUH) wrapped the child in the heavenly cloth, shaved his hair and to the weight of the hair gave silver as charity, perfumed his hair with a scent called Kholooq, scarified a sheep, gave the right leg to the midwife and the rest to the neighbours [2].
[1] Allama Majlesi, Beharul Anwaar, Vol. 43, Page 338.
[2] Ibn Shahr Ashoob, Manaqeb Al-e-Abitaleb, Vol. 3, Page 189.