The Book on General Behaviour (Kitab Al-Adab)
Muslim :: Book 25 : Hadith 5345
Asma' reported that she had become pregnant at Mecca with Abdullah b. Zubair (in her womt) and she (further) said: I set out (for migration to Medina) as I was in the advanced stage of pregnancy. I came to Medina and got down at the place known as Quba' and gave birth to a child there. Then I came to Allah's Messenger (may peace he upon him). He placed him (the child) in his lap and then commanded for the dates to be brought. He chewed them and then put the saliva in his mouth. The first thing which went into his stomach was the saliva of Allah's Messenger (may peace be upon him). He then rubbed his palate with dates and then invoked blessings for him and blessed him. He was the first child who was born in Islam (after Migration).