Sayyiduna Ali (may Allah be pleased with him) narrates that I once submitted in the presence of the Messenger of Allah (peace and blessings be upon him), "O Messenger of Allah! Why do you prefer other families of Quraysh over us?" The Prophet (peace and blessings be upon him) said, "Do you also have something (to offer)?" I replied, "Yes! The daughter of Sayyiduna Hamza (may Allah be pleased with him)!" So the Prophet (peace and blessings be upon him) said, "She is not lawful for me because she is my foster niece." (In fact, the Prophet (peace and blessings be upon him) and Sayyiduna Amir Hamza were foster brothers as well as uncle and nephew to each other.)