It was narrated that Sa’eed bin al-Musayyab said:
‘Ali (رضي الله عنه) said: I said: O Messenger of Allah (ﷺ), shall I not tell you about the most beautiful girl of Quraish? He said: “who is she?` I said: The daughter of Hamzah. He said: `Don`t you know that she is the daughter of my brother through breastfeeding? Allah has forbidden (for marriage) through breastfeeding that which He has forbidden through blood ties.”