It was narrated from 'Amir bin Sa'd that his father said:
"I became sick during the year of the Conquest, and was at death's door. The Messenger of Allah (ﷺ) came to visit me and I said: 'O Messenger of Allah (ﷺ), I have a great deal of wealth and no one will inherit from me apart from my daughter. Can I give two thirds of my wealth in charity?' He said: 'No.' I said: 'Then half?' He said: 'No.' I said: 'One third?' He said: One third and one third is a lot. If you leave your heirs rich that is better than leaving them destitute and begging from people."
English reference: Vol. 3, Book 22, Hadith 2708
Arabic reference: Book 22, Hadith 2812