Sunan an-Nasa'i, Volume 4, Book 30, Hadith 3662 (DarusSalam) ⓘ

It was narrated from Sa'd that the Prophet visited him when he was sick, and he said: "O Messenger of Allah, shall I bequeath all of my wealth?" He said: "No." He said: "Half?" He said: "No." He said: "One-third?" He said: "One-third, and one-third is much or large."

أَخْبَرَنَا إِسْحَاقُ بْنُ إِبْرَاهِيمَ، قَالَ حَدَّثَنَا وَكِيعٌ، قَالَ حَدَّثَنَا هِشَامُ بْنُ عُرْوَةَ، عَنْ أَبِيهِ، عَنْ سَعْدٍ، أَنَّ النَّبِيَّ صلى الله عليه وسلم عَادَهُ فِي مَرَضِهِ فَقَالَ يَا رَسُولَ اللَّهِ أُوصِي بِمَالِي كُلِّهِ قَالَ ‏"‏ لاَ ‏"‏‏.‏ قَالَ فَالشَّطْرَ قَالَ ‏"‏ لاَ ‏"‏‏.‏ قَالَ فَالثُّلُثَ قَالَ ‏"‏ الثُّلُثَ وَالثُّلُثُ كَثِيرٌ أَوْ كَبِيرٌ ‏"‏‏.‏