Sunan an-Nasa'i 3626
It was narrated from 'Amir bin Sa'd that his father said:
"I became ill with a sickness from which I later recovered. The Messenger of Allah came to visit me, and I said: 'O Messenger of Allah, I have a great deal of wealth and I have no heir except my daughter. Shall I give two-thirds of my wealth in charity?' He said: 'No.' I said: 'Half?' He said: 'No.' I said: 'One-third?' He said: '(Give) one-third, and one-third is a lot. It is better to leave your heirs independent of means, than to leave them poor and holding out their hands to people.'"
أَخْبَرَنِي عَمْرُو بْنُ عُثْمَانَ بْنِ سَعِيدٍ، قَالَ حَدَّثَنَا سُفْيَانُ، عَنِ الزُّهْرِيِّ، عَنْ عَامِرِ بْنِ سَعْدٍ، عَنْ أَبِيهِ، قَالَ مَرِضْتُ مَرَضًا أَشْفَيْتُ مِنْهُ فَأَتَانِي رَسُولُ اللَّهِ صلى الله عليه وسلم يَعُودُنِي فَقُلْتُ يَا رَسُولَ اللَّهِ إِنَّ لِي مَالاً كَثِيرًا وَلَيْسَ يَرِثُنِي إِلاَّ ابْنَتِي أَفَأَتَصَدَّقُ بِثُلُثَىْ مَالِي قَالَ ‏"‏ لاَ ‏"‏‏.‏ قُلْتُ فَالشَّطْرَ قَالَ ‏"‏ لاَ ‏"‏‏.‏ قُلْتُ فَالثُّلُثَ قَالَ ‏"‏ الثُّلُثَ وَالثُّلُثُ كَثِيرٌ إِنَّكَ أَنْ تَتْرُكَ وَرَثَتَكَ أَغْنِيَاءَ خَيْرٌ لَهُمْ مِنْ أَنْ تَتْرُكَهُمْ عَالَةً يَتَكَفَّفُونَ النَّاسَ ‏"‏‏.‏