Silsilat al-Ahadith al-Sahihah

Sayyiduna Ali (may Allah be pleased with him) says: When we left Makkah, the daughter of Sayyiduna Hamzah (may Allah be pleased with him) started following us. She called out: "My uncle! My uncle!" I took her hand and, handing her over to Sayyidah Fatimah (may Allah be pleased with her), said: "Keep your cousin with you." When we reached Madinah, I, Zayd, and Ja'far began to dispute. I said: "She is my uncle's daughter and I have brought her." Zayd said: "She is my brother's daughter," and Ja'far said: "She is my uncle's daughter and her maternal aunt is my wife." The Messenger of Allah (peace and blessings of Allah be upon him) said to Ja'far: "You resemble me in both appearance and character." He said to Zayd: "You are our brother and friend." And he said to me: "You are from me and I am from you." Then he said: "Hand her (the girl) over to her maternal aunt, for the maternal aunt is like the mother." I said: "O Messenger of Allah! Why don't you marry her?" The Prophet (peace and blessings of Allah be upon him) said: "She is the daughter of my foster brother (Sayyiduna Hamzah, may Allah be pleased with him)."