Narrated Asma:
That she conceived `Abdullah bin Az-Zubair. She added, "I migrated to Medina while I was at full term of pregnancy and alighted at Quba where I gave birth to him. Then I brought him to the Prophet (ﷺ) and put him in his lap. The Prophet (ﷺ) asked for a date, chewed it, and put some of its juice in the child's mouth. So, the first thing that entered the child's stomach was the saliva of Allah's Messenger. Then the Prophet rubbed the child's palate with a date and invoked for Allah's Blessings on him, and he was the first child born amongst the Emigrants in the Islamic Land (i.e. Medina).
Narrated Asma' bint Abu Bakr:
I conceived `Abdullah bin AzZubair at Mecca and went out (of Mecca) while I was about to give birth. I came to Medina and encamped at Quba', and gave birth at Quba'. Then I brought the child to Allah's Messenger (ﷺ) and placed it (on his lap). He asked for a date, chewed it, and put his saliva in the mouth of the child. So the first thing to enter its stomach was the saliva of Allah's Messenger. Then he did its Tahnik with a date, and invoked Allah to bless him. It was the first child born in the Islamic era, therefore they (Muslims) were very happy with its birth, for it had been said to them that the Jews had bewitched them, and so they would not produce any offspring.
'Urwa b. Zubair and Fatima daughter of Mandhir b. Zubair, reported that Asma' daughter of Abu Bakr was at the time of migration in the family way with 'Abdullah b. Zubair (in her womb). She came to Quba' and gave birth to 'Abdullah at that place and then sent him to Allah's Messenger (ﷺ) so that he should rub his palate with chewed dates. Allah's Messenger (may peace he upon him) took hold of him (the child) and he placed him in his lap and then called for dates. 'A'isha said: Some time was spent before we were able to find them. He (the Holy Prophet) chewed them and then put his saliva in his mouth. The first thing that entered his stomach, was the saliva of Allah's Messenger (ﷺ). Asma' said: He then rubbed him and blessed him and gave him the name of Abdullah. He ('Abdullah) went to him (the Holy Prophet) when he had attained the age of seven or eight years in order to pledge allegiance to Allah's Messenger (ﷺ) as Zubair had commanded him to do. Allah's Messenger (ﷺ) smiled when he saw him coming towards him and then accepted his allegiance.