Is a mother giving a sum of money to her son to buy a car, with the daughter promising a third of this amount later, considered just among the children or not?

A mother must be fair among her children in giving gifts. Preferring some over others without a valid reason, such as need or destitution, is considered an injustice, based on the Prophet Muhammad's (peace be upon him) saying: "Fear Allah and be just among your children." However, if a mother singles out one of her children due to need or destitution, there is no harm in that, and she is not obligated to give the rest of her children what she gave to that one. Scholars have differed on how to be just between male and female children. Some are of the view that a male should receive twice the share of a female, while others hold that equality between them is required. This latter opinion is the more apparent one, based on his (peace be upon him) saying: "Be equal among your children in giving gifts."