Waki' bin al-Jarrah وكيع بن الجراح · The Book of Wills

"They say that the Messenger of Allah made a will concerning 'Ali, may Allah be pleased with him. But he called for a vessel in which to urinate, then he went limp without me realizing it. So to whom did he leave a will?"

"My mother has died and she had a vow to fulfill. Will it suffice if I free a slave on her behalf?" He said: "Free a slave on behalf of your mother."

"Fulfill it on her behalf."