Muwatta Imam Malik (Riwayat Yahya)

The mother of Abdur Rahman bin Abi Amrah intended to make a will, but delayed it until morning, and she died during the night. Her intention was to free a slave. Abdur Rahman said: I asked Qasim bin Muhammad: If I free (a slave) on behalf of my mother, will she benefit from it? Qasim said: Sa’d bin Ubadah asked the Messenger of Allah, peace and blessings be upon him, that my mother has died; if I free (a slave) on her behalf, will she benefit from it? The Prophet, peace and blessings be upon him, said: “Yes.”

Yahya ibn Sa'id said: Abdur Rahman ibn Abu Bakr died in his sleep. Lady Aisha, may Allah be pleased with her, freed many slaves on his behalf.
Imam Malik, may Allah have mercy on him, said that he liked this narration very much in this chapter.