Sunan an-Nasa'i 3660

Al-Harith bin Miskin said—while the report was being read to him and I was listening—that it was transmitted from Sufyan, from al-Zuhri, from Ubaidullah bin Abdullah, from Ibn Abbas, that Sa'd bin Ubadah asked the Prophet about a vow his mother had owed. She died before fulfilling it, so the Messenger of Allah said, ‘Fulfill it on her behalf.’