It is repeatedly stated in the law of inheritance mentioned in the Qur'an that the inheritance should be distributed after disbursing any will made by the deceased. Two questions arise on this.
First, is there a limit imposed on the amount a person can will in favour of someone or does he have the discretion to will any amount he wants to?
Second, can a will be made in favour of people who have been made the heirs of the deceased by the Almighty?
The answer to the first question is that the words of the Qur'an impose no limit on the amount that is to be willed. The Almighty has unconditionally mentioned that this distribution of inheritance shall take place once the will of the deceased has been executed. No limit can be imposed on this willed amount as per the dictates of language and style of the relevant verses. The narrative which is attributed to the Prophet (sws) in this regard has an entirely different connotation: one of his companions expressed his wish before him that after his death he wanted to donate all his wealth for the cause of God. The Prophet (sws) replied that this would be too big an amount given for this purpose and that if a person has wealth, he should not leave his heirs empty-handed. The companion then asked if he could donate two thirds and later asked if he could reserve half of his wealth for this purpose. At this, the Prophet (sws) gave him the same reply. The companion further asked if he could give one-third of his wealth. The Prophet (sws) responded by saying that this was quite enough.Everyone can see that this was a comment of the Prophet (sws) in a particular case. It cannot be regarded as a legal limit imposed by the Prophet (sws).
The answer to the second question is that the Almighty Himself has made a will in favour the heirs of a deceased. So no Muslim can dare make a will in this regard. Thus, on the basis of familial relationship, no will can be made in their favour; however, a will can certainly be made in favour of these very heirs because of some need they may have or because of some service they may have rendered for the deceased or because of any similar matter. Thus if one of the children of a person is school going and as such is not earning while others are, or if one of the children has served his parents more than the others, or if aperson fears that after his demise there will be no one to look after and provide for his wife, then a will can be made in favour of each of these. Just as a will can be made in favour of friends or for the purpose of charity, it can similarly be made in favour of these heirs. There is nothing in the shari'ah which hinders it.
(Translated by Dr Shehzad Saleem)
. Al-Bukhari, Al-Jami' al-sahih, vol. 3, 1006, (no. 2591); Muslim, Al-Jami' al-sahih, vol. 3, 1253, (no. 1628).