Sunan an-Nasa'i, Volume 4, Book 30, Hadith 3661 (DarusSalam) ⓘ

It was narrated that Sa'd bin Abi Waqqas said: "The Messenger of Allah visited me when I was sick, and said: 'Have you made a will?' I said: 'Yes.' He said: 'How much?' I said: 'For all my wealth to be given in the cause of Allah.' He said: 'What have you left for your children?' I said: 'They are rich (independent of means).' He said: 'Bequeath one-tenth.' And we kept discussing it until he said: 'Bequeath one-third, and one-third is much or large.'"

أَخْبَرَنَا إِسْحَاقُ بْنُ إِبْرَاهِيمَ، قَالَ أَنْبَأَنَا جَرِيرٌ، عَنْ عَطَاءِ بْنِ السَّائِبِ، عَنْ أَبِي عَبْدِ الرَّحْمَنِ، عَنْ سَعْدِ بْنِ أَبِي وَقَّاصٍ، قَالَ عَادَنِي رَسُولُ اللَّهِ صلى الله عليه وسلم فِي مَرَضِي فَقَالَ ‏"‏ أَوْصَيْتَ ‏"‏‏.‏ قُلْتُ نَعَمْ‏.‏ قَالَ ‏"‏ بِكَمْ ‏"‏‏.‏ قُلْتُ بِمَالِي كُلِّهِ فِي سَبِيلِ اللَّهِ‏.‏ قَالَ ‏"‏ فَمَا تَرَكْتَ لِوَلدِكَ ‏"‏‏.‏ قُلْتُ هُمْ أَغْنِيَاءُ‏.‏ قَالَ ‏"‏ أَوْصِ بِالْعُشْرِ ‏"‏‏.‏ فَمَا زَالَ يَقُولُ وَأَقُولُ حَتَّى قَالَ ‏"‏ أَوْصِ بِالثُّلُثِ وَالثُّلُثُ كَثِيرٌ أَوْ كَبِيرٌ ‏"‏‏.‏