Musnad Abu Ya'la al-Mawsili 3:120

Ishaq ibn Isma'il al-Taliqani narrated to us, Jarir narrated to us, from al-A'mash, from Sa'd ibn 'Ubaydah, from Abu 'Abd al-Rahman al-Sulami, from 'Ali, who said: I said, "O Messenger of Allah, why do you choose from the women of Quraysh and leave us?" He said, "Do you have anything?" I said, "Yes, the daughter of Hamzah." The Prophet, may Allah bless him and grant him peace, said, "She is only the daughter of my brother through breastfeeding."