Maliks Muwatta Book 038, Hadith Number 014.

Section : Freeing the Living for the Dead.

Malik related to me that Yahya ibn Said said, "Abd ar-Rahman ibn Abi Bakr died in his sleep, and A'isha, the wife of the Prophet, may Allah bless him and grant him peace, set free many slaves for him." Malik said, "This is what I like best of what I have heard on the subject."