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.