Chapter 30: The Book of Wills
It was narrated from 'Aishah that the Messenger of Allah came to visit Sa' d (when he was sick). Sa' d said to him: "O Messenger of Allah, shall I bequeath two-thirds of my wealth?" He said: "No." He said: "Shall I bequeath half?" He said: "No." He said: "Shall I bequeath one-third?" He said: "Yes, one-third, and one-third is much or large. If you leave your heirs independent of means that is better than if you leave them poor, holding out their hands."
Sunan an-Nasa'i 3633