Khalid bin 'Abdullah al-Tahan خالد بن عبد الله بن عبد الرحمن الطحان · The Book of Wills

"If the people were to reduce (their bequests) to one-quarter (of their wealth, that would be better), because the Messenger of Allah said: 'One-third, and one-third is much or large.'"

"From Sufyan, from Az-Zuhri, from 'Ubaidullah bin 'Abdullah, from Ibn 'Abbas, that Sa'd bin 'Ubadah consulted the Prophet about a vow which his mother had to fulfill, but she died before doing so. The Messenger of Allah said: 'Fulfill it on her behalf.'"