(14) باب ابْنُ أُخْتِ الْقَوْمِ وَمَوْلَى الْقَوْمِ مِنْهُمْ
Narrated Anas:
The Prophet (ﷺ) sent for the Ansar (and when they came), he asked, 'Is there any stranger amongst you?" They said, "No except the son of our sister." Allah's Messenger (ﷺ) said, "The son of the sister of some people belongs to them."
Reference: Sahih al-Bukhari 3528
In-book reference: Book 61, Hadith 38
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 4, Book 56, Hadith 729