Is a father's division of his estate among his children—favoring some over others and disinheriting one of them—considered a lawful and just division? And what is the just division of an estate?

A father must be fair in giving gifts to his children. It is not permissible for him to favor one over another with a gift unless there is a legitimate Sharia reason, based on the Prophet Muhammad's (peace be upon him) saying: "Fear Allah and be just among your children." Scholars have differed on the manner of justice: whether the male should receive the equivalent of two females' shares, or if male and female should be equal in the gift. The Malikis, Shafi'is, Hanafis, and Hanbalis adopted the second opinion, which is the equality of male and female. The father must revoke what he specifically gave to one child, or give the others the same amount he gave.