The Sale of a Man Over the Sale of His Brother is Not Allowed

Question

Praise be to Allah.

It is not
permissible for a Muslim to undersell his brother, because it is proven in
al-Saheehayn that the Prophet (peace and blessings of Allah be upon
him) said: “No man should sell over his brother.”

The wisdom behind
this prohibition is that it provokes enmity and hatred among Muslims, and
everything that leads to enmity and hatred among Muslims is haram, because
of the general meaning of the verse in which Allah says (interpretation of
the meaning):

“Shaytan (Satan)
wants only to excite enmity and hatred between you with intoxicants
(alcoholic drinks) and gambling”

[al-Maidah 5:91]

Allah has stated
that the reason for the prohibition on alcohol and gambling is that it leads
to enmity and hatred for those who do those things.

Secondly:

If a Muslim
undersells his brother, is the transaction valid or not? There are two
scholarly points of view. Some of them said that it is not valid, which is
the view of the Hanbalis, and some said that the transaction is valid but
sinful, which is the view of al-Shafi’i (may Allah have mercy on him).

Ibn Qudamah (may
Allah have mercy on him) said in al-Mughni (4/149): If he goes
against that and does the transaction, then the transaction is invalid,
because it is forbidden, and the prohibition implies that it is invalid. And
it is possible that it may be valid, because what is forbidden is offering
his product to the buyer or saying something for which he cancels the
transaction before the transaction has been completed, and because if the
annulment of the transaction which causes harm is valid, then going ahead
with the (second) transaction should also be valid, and because the
prohibition has to do with protecting the rights of another person, so it is
similar to artificial inflation of prices. This is the view of al-Shafi’i.

Al-Mardawi said in
al-Insaf (4/331): it is not permissible for a man to undersell his
brother, which means saying to one who has bought a product for ten: I will
give you something similar for nine. And it is not permissible for a man to
falsely tempt (outbid) his brother, which is when he says to someone who has
bought a product for nine: I will give ten for it, in order to cancel the
sale and make a deal with him. There is no difference of scholarly opinion
concerning this. This may occur in two cases: before the two parties
conclude the deal and part, or when the deal is conditional. … In answer to
the question “If he does that, is it valid?” there are two views, both of
which are narrated in al-Furoo’ and elsewhere.

1 – It – i.e., the
second transaction – is not valid. This is our point of view, and it was
classed as sound in al-Tasheeh. It says in al-Madhhab wa Masbook
al-Dhahab: the transaction is invalid according to the apparent view. It
says in al-Furoo’: It is not valid according to the more correct
opinion. It says in al-Ri’ayah al-Kubra: The better known view is
that it is invalid. This view was favoured by Abu Bakr and others, and it
was confirmed in al-Khalasah, al-Wajeez, and Tadhkirat Ibn
‘Abdoos. It was also given precedence in al-Sharh and al-Kafi.

2 – It is valid.
This was the view favoured by al-Qadi and Abu’l-Khattaab. Shaykh Taqiy
al-Deen said: It is haram to outbid one’s brother, and if he does that the
first purchaser has the right to demand the product from the seller and take
the extra amount or compensation. End quote.

See:
al-Mawsoo’ah al-Fiqhiyyah (9/214)

Al-Shaykh ibn
‘Uthaymeen (may Allah have mercy on him) said: The words “the transaction is
invalid” clearly show that the transaction is not valid, but some of the
scholars say that the transaction is valid, because the prohibition here
does not refer to the trade goods, rather it refers to something else,
namely the transgression against the rights of another Muslim, so the
transaction is haram, but it is still valid. This may be proven by the fact
that if the one who undersold his brother gets permission from the one whom
he undersold, then the transaction is valid and there would be nothing wrong
with it. Therefore, the transaction is valid but sinful.

But to adopt the
view of the madhhab is better because it prevents people from transgressing
against the rights of others. End quote from al-Sharh al-Mumti’
(8/206).

And Allah knows
best.