When we left Mecca, the daughter of Hamza followed us, calling out, "Uncle, uncle!" Ali said, "I took her by the hand and handed her over to Fatimah, saying, 'Take your cousin.'"When we arrived in Medina, Jafar, Zayd bin Haritha, and I disputed over her custody.Jafar said, "She is my cousin, and her maternal aunt is my wife," meaning Asma bint Umays.Zayd said, "She is the daughter of my brother."I said, "I am the one who took her, and she is my cousin."The Messenger of Allah ﷺ said, "As for you, Jafar, you resemble me in appearance and character. As for you, Ali, you are from me and I am from you. As for you, Zayd, you are our brother and our freedman. The girl shall stay with her maternal aunt, for the maternal aunt holds the position of a mother."I asked, "Messenger of Allah, will you not marry her?"He replied, "She is the daughter of my brother through breastfeeding."
لما خرجنا من مكة اتبعثنا ابنة حمزة تنادي: يا عم يا عم قال: فتناولتها بيدها، فدفعتها إلى فاطمة، فقلت: دونك ابنة عمك. قال: فلما قدمنا المدينة اختصمنا فيها أنا وجعفر وزيد بن حارثة. فقال جعفر: ابنة عمي، وخالتها عندي، يعني أسماء بنت عميس، وقال زيد: ابنة أخي، وقلت: أنا أخذتها وهي ابنة عمي. فقال رسول الله ﷺ: أما أنت يا جعفر فأشبهت خلقي وخلقي، وأما أنت يا علي فمني وأنا منك، وأما أنت يا زيد فأخونا ومولانا. والجارية عند خالتها، فإن الخالة والدة قلت: يا رسول الله! ألا تتزوجها؟ قال: إنها ابنة أخي من الرضاعة
Narrated by Abu Dawud (2280) and Ahmad (770), and Hakim graded it sahih (3/120), all of them through the route of Abu Ishaq, from Hani bin Hani and Hubayra bin Yarim, from Ali, who related it.Its chain of transmission is hasan on account of Hani bin Hani and Hubayra, since both of them are acceptable narrators, each strengthening the other. This story has also been narrated from Ali through another route as well, in Sunan Abu Dawud and elsewhere. Both hadiths are preserved from Bara and Ali bin Abu Talib, and it has also been narrated from other companions. What is sahih among these is only what has come from Bara and Ali.