'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.