Merits of the Helpers in Madinah (Ansaar)

Bukhari :: Book 5 :: Volume 58 :: Hadith 249

Narrated Aisha:

The first child who was born in the Islamic Land (i.e. Medina) amongst the Emigrants, was 'Abdullah bin Az-Zubair. They brought him to the Prophet. The Prophet took a date, and after chewing it, put its juice in his mouth. So the first thing that went into the child's stomach, was the saliva of the Prophet