It was narrated that 'Ali, may Allah be pleased with him, said:"I said: 'O Messenger of Allah, why do you choose wives from among Quraish and not from among us?' He said: 'Do you have anyone in mind?' I said: 'Yes, the daughter of Hamzah.' The Messenger of Allah said: 'She is not permissible for me (to marry); she is the daughter of my brother through breast-feeding

English translation · Sunan an-Nasa'i