Muwatta Malik #1336

Yahya related to me from Malik from Nafi that Safiyya bint Abi Ubayd told him that Hafsa, umm al-muminin, sent Asim ibn Abdullah ibn Sad to her sister Fatima bint Umar ibn al-Khattab for her to suckle him ten times so that he could come in to see her. She did it, so he used to come in to see her.