Anas b. Malik reported:

I took 'Abdullah b. Abi Talha Ansari to Allah's Messenger (ﷺ) at the time of his birth. Allah's Messenger (ﷺ) was at that time wearing a woollen cloak and besmearing the camels with tar. He said: Have you got with you the dates? I said: Yes. He took hold of the dates and put them in his mouth and softened them, then opened the mouth of the infant and put that in it and the child began to lick it. Thereupon Allah's Messenger (ﷺ) said: The Ansar have a liking for the dates, and he (the Prophet) gave him the name of 'Abdullah.

حَدَّثَنَا عَبْدُ الأَعْلَى بْنُ حَمَّادٍ، حَدَّثَنَا حَمَّادُ بْنُ سَلَمَةَ، عَنْ ثَابِتٍ الْبُنَانِيِّ، عَنْ أَنَسِ، بْنِ مَالِكٍ قَالَ ذَهَبْتُ بِعَبْدِ اللَّهِ بْنِ أَبِي طَلْحَةَ الأَنْصَارِيِّ إِلَى رَسُولِ اللَّهِ صلى الله عليه وسلم حِينَ وُلِدَ وَرَسُولُ اللَّهِ صلى الله عليه وسلم فِي عَبَاءَةٍ يَهْنَأُ بَعِيرًا لَهُ فَقَالَ ‏"‏ هَلْ مَعَكَ تَمْرٌ ‏"‏ ‏.‏ فَقُلْتُ نَعَمْ ‏.‏ فَنَاوَلْتُهُ تَمَرَاتٍ فَأَلْقَاهُنَّ فِي فِيهِ فَلاَكَهُنَّ ثُمَّ فَغَرَ فَا الصَّبِيِّ فَمَجَّهُ فِي فِيهِ فَجَعَلَ الصَّبِيُّ يَتَلَمَّظُهُ فَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏"‏ حُبُّ الأَنْصَارِ التَّمْرَ ‏"‏ ‏.‏ وَسَمَّاهُ عَبْدَ اللَّهِ ‏.‏