Nasai

(1) Once an item has been sold, the first owner is no longer the owner; rather, the buyer becomes the owner. If the first owner sells it elsewhere, he will be selling someone else’s property; therefore, the second sale will not be valid. Similarly, if a thief or a robber sells someone else’s property, that sale will not be valid; rather, the item will remain the property of the original owner. If the original owner gains access to the item, he may take it back without compensation. (See Fawa’id wa Masa’il, Hadith: 4683) In the matter of marriage (nikah) as well, when one guardian (wali) has conducted the marriage, the action of another guardian is not valid.

(2) This hadith does not correspond with the chapter heading. The author, rahimahullah, should have established a separate chapter heading (tarjamat al-bab) for this hadith, with which the relevance of the hadith would have been clear.

Commentary:
Note:
(Hasan al-Basri is a mudallis and has narrated this hadith with ‘an‘anah.
Also, there is a difference of opinion regarding Hasan’s hearing of hadith from Samurah radi Allahu anhu, except for the hadith of ‘aqiqah.
However, the issue is established from other texts.)

Benefits and Issues:

➊
By “the person in authority” is meant the guardian of an orphan or minor, who has the authority to buy and sell on their behalf. (Al-Nihayah)
This also refers to any ordinary person whose buying and selling is legally and Islamically permissible.

➋
An example of two individuals selling is as follows: a certain item was jointly owned by two people.
Each of them, without informing the other, sold it separately, or for example:
An agent (wakil) sold it, and the principal (owner) also, without informing the agent, sold the same item to someone else. In such a case, the sale that was conducted first will be considered valid, and the sale conducted later will be nullified.
And Allah knows best.

Takhrij:
«أخرجه أبوداود، النكاح، باب إذا أنكاح الوليان، حديث:2088، والترمذي، النكاح.حديث:1110، والنسائي، البيوع، حديث:4686، وابن ماجه، التجارات، حديث:2190، وأحمد:5 /8، 18.»©

Explanation:
➊ From this hadith, it is understood that if a woman’s two guardians (wali) marry her to two different men at different times, then she will be considered the wife of the man with whom the marriage (nikah) was contracted first, and the second marriage will automatically be rendered void, because the Shari‘ah has declared it impermissible to contract a marriage upon an existing marriage.
And if both marriages are contracted simultaneously, then both will be considered void; neither will be valid.
➋ However, if the woman wishes to maintain one of the two marriages, or if one of the two men has already had valid seclusion (khalwah sahihah) with her with her consent, then that marriage can remain intact.