English Translation
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
This hadith is from Sahih al-Bukhari, the most rigorously authenticated collection in Islamic scholarship. No editorial opinion is added.