Case 1: A woman leaves behind a husband and two sisters. The prescribed shares are as follows:
Heir |
Applicable Text |
Prescribed share |
Equivalent fraction |
Percentage |
Husband |
4:12 ولكم نصف |
1/2 |
3/6 |
50 % |
Sisters |
4:176 فلهما الثلثان |
2/3 |
4/6 |
66.67 % |
It is not possible to give the heirs their prescribed shares, since if the husband is given 50% then only 50% is left which is less than ~67% required by the sisters.
The solution is to divide the shortfall proportionally among all the heirs. This is called 'awl (عَوْل) and is based on:
- the Ijma' of the sahaba at the time of the caliphate of Umar ibn al-Khatab.
- analogy with the case of person who dies, and owes debts to multiple lenders, but does not have enough money to repay them all
So the estate is distributed as follows:
Heir |
|
Original share |
Adjusted |
Percentage |
Husband |
|
3/6 |
3/7 |
42.86 % |
Sisters |
|
4/6 |
4/7 |
57.14 % |
Case 2: A man leaves behind a wife, a daughter, a father and a mother.
In this you have made a mistake in your calculation, as the share of a (single) daughter is 1/2 not 2/3. If you meant multiple daughters then 'awl will apply like the above. But I will address what you have written (single daughter) as this covers a different rule, i.e. ta'sib.
The prescribed shares are as follows:
Heir |
Applicable Text |
Prescribed Share |
Equivalent Fraction |
Percentage |
Wife |
4:12 فلهن الثمن |
1/8 |
3/24 |
12.5 % |
Daughter |
4:11 فلها النصف |
1/2 |
12/24 |
50 % |
Father |
4:11 كل واحد منهما السدس |
1/6 |
4/24 |
16.67 % |
Mother |
4:11 كل واحد منهما السدس |
1/6 |
4/24 |
16.67 % |
After each of these has been given their prescribed shares, 1/24 or 4.17 % of the estate still remains. This will be given to the closest male relative (the father) in accordance to the hadith:
ألحقوا الفرائض بأهلها فما بقي فهو لأولى رجل ذكر
Give the shares to those who are entitled to them, and what remains over goes to the nearest male heir.
— Bukhari and Muslim
Hence the final distribution will be:
Heir |
|
Prescribed Share |
Additional share |
Percentage |
Wife |
|
3/24 |
|
12.5 % |
Daughter |
|
12/24 |
|
50 % |
Father |
|
4/24 |
1/24 |
20.83 % |
Mother |
|
4/24 |
|
16.67 % |
Why does the Quran need to be corrected??
There is no mistake which needs to be corrected. The prescribed shares can be distributed "as is" in many cases. It is only in certain combinations of prescribed shares where exact distribution is not possible, and in these cases the Quran is at most silent about what to do ... not 'mistaken'.
You are falsely assuming that the Quran says "if a woman dies leaving a husband and sisters then give the husband 1/2 and the sisters 2/3". It does not say that at all. Rather it says in isolation that a husband gets 1/2 and that in isolation two sisters get 2/3. The first verse will apply just fine in several cases where the deceased does not have sisters, and the second one will apply just fine in several cases where the deceased does not have a husband. It is only the novel case where both are combined that the problem arises. And the Quran makes no claim that its prescribed shares will hold when this happens.
The Quran does not claim that the prescribed shares will always add up to one. The Quran does not claim that it covers all cases of inheritance within its text. The Quran is not the only source of Islamic law, rather Sunnah, Ijtihad, Ijma', Qiyas etc. complement the Quran in situations which it does not explicitly cover.
أطيعوا الله وأطيعوا الرسول وأولي الأمر منكم فإن تنازعتم في شيء فردوه إلى الله والرسول
Obey Allah and obey the Messenger and those in authority among you. And if you disagree over anything, refer it to Allah and the Messenger
— Quran 4:59
اقض بما في كتاب الله فإن لم يكن في كتاب الله فبسنة رسول الله صلى الله عليه وسلم فإن لم يكن في كتاب الله ولا في سنة رسول الله صلى الله عليه وسلم فاقض بما قضى به الصالحون
Judge according to what is in the Book of Allah. If it is not (mentioned) in the Book of Allah, then (judge) according to the Sunnah of the Messenger of Allah ﷺ. If it is not (mentioned) in the Book of Allah or the Sunnah of the Messenger of Allah ﷺ, then pass judgment according to the way the righteous passed judgment.
— Nasai
The two cases which you have asked about are not detailed in the Quran, rather they are dealt with in the other sources of law which are authorized by the Quran.
Let me also illustrate this with a different example: The Quran commands us to wash our hands in wudu.
اغسلوا وجوهكم وأيديكم إلى المرافق
wash your faces and your hands up to the elbows
— Quran 5:6
Now there is a case of an amputee who can not wash his hands as they do not exist. Will you say that this verse is wrong and needs to be corrected?
No - rather the verse is correct and applicable to most situations, it just does not specify what to do in this exceptional case. And the other sources explain that such a person will follow as much of the verse as as he is able to and will omit what is not possible for him. The same applies to the cases of inheritance which you have asked about.