Sunan an-Nasa'i 3306
سنن النسائي#3306SahihIt was narrated from Ibn 'Abbas that the daughter of Hamzah was suggested to Messenger of Allah (as a potential wife). He said:"She is the daughter of my brother through breast-feeding, and what becomes unlawful (for marriage) through breast-feeding is the same as that which becomes unlawful through lineage
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Abu GhuddahSahih
Al-AlbaniSahih
Zubair Ali ZaiHasan
In-book reference: 26:111