Sahih Muslim | Book 8 | Chapter 6

Narrated by Ibn Umar (Allah be pleased with them)
Ibn Umar (Allah be pleased with them) reported Allah's Apostle (may peace be upon him) as having said this: None amongst you should outbid another in a transaction, nor should he make proposals of marriage upon the proposal made by someone else.

Narrated by Ibn Umar (Allah be pleased with them)
Ibn Umar (Allah be pleased with them) reported Allah's Apostle (may peace be upon him) as having said this: A person should not enter into a transaction when his brother (had already entered into but not finalised), and he should not make proposal of marriage upon the proposal already made by his brother, until he permits it.

Narrated by
A hadith like this has been reported on the authority of Nafi' with the same chain of transmitters.

Narrated by Abu Huraira (Allah be pleased with him)
Abu Huraira (Allah be pleased with him) reported Allah's Apostle (may peace be upon him) as having forbidden a dweller of the town selling the merchandise of a villager or outbidding in a sale (in order that another might fall into a snare), or a person making the proposal of marriage when his brother has already made such a proposal, or entering into a transaction when his brother has already entered; and a woman asking the divorce of her sister in order to deprive her of what belongs to her. 'Amr made this addition: "The person should not purchase in opposition to his brother.

Narrated by Abu Huraira (Allah be pleased with him)
Abu Huraira (Allah be pleased with him) reported Allah's Messenger (may peace be upon him) as having said this: Do not outbid in a sale in order to ensnare. No man should enter into a transaction in which his brother has already entered, and no dweller of the town should sell on behalf of the villager. And no man should make a proposal of marriage which his brother has already made and no woman should ask for the divorce of another (co-wife) in order to deprive her of what belongs to her.

Narrated by Zuhri
A hadith like this has been narrated on the authority of Zuhri with the same chain of transmitters but with a slight alteration.
Narrated by Abu Huraira (Allah be pleased with him)
Abu Huraira (Allah be pleased with him) reported Allah's Messenger (may peace be upon him) as saying: The Muslim should not purchase in opposition to his brother, and he should not make the proposal of marriage on the proposal already made by his brother.

Narrated by Abu Huraira
This hadith has been narrated on the authority of Abu Huraira (Allah be pleased with him) through another chain of transmitters.

Narrated by 'Uqba b. 'Amir
'Uqba b. 'Amir said on the pulpit that Allah's Messenger (may peace be upon him) said: A believer is the brother of a believer, so it is not lawful for a believer to outbid his brother, and he should not propose an engagement when his brother has thus proposed until he gives it up.