(34) باب الرَّجُلِ يُكَنَّى قَبْلَ أَنْ يُولَدَ لَهُ
It was narrated that Anas said:
"The Prophet(ﷺ) used to come to us and say to a brother of mine, who was small: 'O Abu Umair.'".
Reference: Sunan Ibn Majah 3740
In-book reference: Book 33, Hadith 85
English translation: Vol. 5, Book 33, Hadith 3740