Hadith 6:1284
Waki’ narrated to us, from Sufyan, from Habib ibn Abi Thabit, from ‘Ata’, Sufyan, and Zayd ibn Aslam, they said: A man came to the Prophet, may Allah bless him and grant him peace, and said: "O Messenger of Allah, shall I free [a slave] on behalf of my father, and he has already died?" He said: "Yes."
حدثنا وكيع عن سفيان عن حبيب بن أبي ثابت عن عطاء وسفيان وزيد بن أسلم قالوا جاء رجل إلى النبي صلى الله عليه وسلم فقال يا رسول الله اعتق ( ( ( أأعتق ) ) ) عن أبي وقد مات قال نعم