Sahih Bukhari Volume 004, Book 051, Hadith Number 010.
Hadith Section/Book: Sahih Bukhari Sahih Bukhari Book 51. Wills and Testaments (Wasaayaa)
Narated By Ibn 'Abbas : The custom (in old days) was that the property of the deceased would be inherited by his offspring; as for the parents (of the deceased), they would inherit by the will of the deceased. Then Allah cancelled from that custom whatever He wished and fixed for the male double the amount inherited by the female, and for each parent a sixth (of the whole legacy) and for the wife an eighth or a fourth and for the husband a half or a fourth.