(5) بَاب اسْتِحْبَابِ تَحْنِيكِ الْمَوْلُودِ عِنْدَ وِلَادَتِهِ وَحَمْلِهِ إِلَى صَالِحٍ يُحَنِّكُهُ وَجَوَازِ تَسْمِيَتِهِ يَوْمَ وِلَادَتِهِ وَاسْتِحْبَابِ التَّسْمِيَةِ بِعَبْدِ اللَّهِ وَإِبْرَاهِيمَ وَسَائِرِ أَسْمَاءِ الْأَنْبِيَاءِ عَلَيْهِمْ السَّلَام
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 (ﷺ). 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).
Reference: Sahih Muslim 2146 b
In-book reference: Book 38, Hadith 32
USC-MSA web (English) reference(deprecated numbering scheme): Book 25, Hadith 5345