Hisham bin Urwah narrated from his father: Asma' bint Abi Bakr (may Allah be pleased with them both) set out, emigrating to the Prophet (peace and blessings be upon him), while she was pregnant with Abdullah bin al-Zubayr. Her labour began, and then she brought him to the Prophet (peace and blessings be upon him) so that he (peace and blessings be upon him) might perform tahnik for him (rub a chewed date on his palate). The messenger of allah (peace and blessings be upon him) took him and placed him in his lap. Then a date was brought; he (peace and blessings be upon him) chewed it, then put it in his mouth and performed tahnik with it. So the very first thing that entered his stomach was the saliva of the Messenger of Allah (peace and blessings be upon him). Asma' (may Allah be pleased with her) said: Then the Messenger of Allah (peace and blessings be upon him) wiped him with his hand and named him Abdullah. Later, when he was seven or eight years old, he came to pledge allegiance to the Prophet (peace and blessings be upon him); al-Zubayr (may Allah be pleased with him) had instructed him to do so. The messenger of allah (peace and blessings be upon him) smiled when he saw him coming, and accepted his pledge. He was the first child born in Islam in Madinah after the arrival of the Messenger of Allah (peace and blessings be upon him). The Jews used to say: "We have bewitched them, so no child will be born to them in Madinah." So when Abdullah was born, the Companions of the Messenger of Allah (peace and blessings be upon him) proclaimed the takbir. When Abdullah bin Umar bin al-Khattab (may Allah be pleased with them both) heard the takbir of the people of Syria, after they had killed Abdullah bin al-Zubayr, he said: "Those who proclaimed the takbir at his birth are better than those who proclaimed the takbir at his killing."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 13818