It is narrated from Mansur (ibn al-Mu'tamir): Ibrahim (may Allah have mercy on him) said: Among the people, one-sixth (for bequest) was more beloved than one-third.
Hadith Referenceسنن دارمي / من كتاب الوصايا / 3234
Hadith Gradingتحقیق (حسین سلیم أسد الدارانی):إسناده صحيح إلى إبراهيم، [مكتبه الشامله نمبر: 3245]
Hadith Takhrijاس اثر کی سند صحیح ہے۔ دیکھئے: [ابن أبى شيبه 10975] ، [عبدالرزاق 16365] ، [ابن منصور 337]
Brief Explanation
(Commentary on Hadiths 3231 to 3234)
From all these traditions, it becomes clear that the deceased should make a bequest (wasiyyah) of less than one third from his wealth, because one third is a limit; the bequest should be for less than this.