Bukhari

Hadith Commentary:
➊
The legal principle in transactions is that the claimant must present evidence, and if he cannot present evidence, then the one against whom the claim is made can clear himself of the accusation by taking an oath.
In certain specific circumstances, a decision can also be made by having the claimant take an oath, as occurs in the case of Qasamah.
➋
The rule is that, regardless of the specific context of revelation (shaan-e-nuzool) of a verse, the general meaning of the verse is acted upon. Accordingly, following this rule, Ibn Abbas (radi Allahu anhu) instructed the woman to recite the aforementioned verse in her presence.
Hafiz Ibn Hajar (rahimahullah) states:
In this hadith, there is an indication towards this very rule, and it is also established that one may admonish and advise someone by using this verse as a basis when intending to have them take an oath.
(Fath al-Bari: 8/269)

Hadith Commentary: Benefits and Issues: This hadith establishes that a person's statement cannot be accepted solely on the basis of his claim. Rather, it is necessary for him to present evidence for his claim, that is, witnesses, or for the defendant to accept his claim. Because if a person's demand is accepted merely on the basis of his claim and his right is acknowledged, then many people will begin to make claims against the lives and property of others, and people's lives and property will become unsafe. Whereas, for the protection of life and property, the claimant has the means of testimony available.

"Al-yamin 'ala al-mudda'a 'alayh" (The oath is upon the defendant): The majority have deduced from this that in the case of a claim, if the claimant cannot present testimony, then in every situation the defendant must take an oath. However, the position of Imam Malik is that the oath is only obligatory upon the defendant when he has some interaction and association with the claimant (the one making the claim). Otherwise, disreputable people would make claims against the honorable in order to harass them, and they would be forced to take oaths repeatedly without reason. Thus, for the validity of a claim, it is a condition that there be some kind of connection or relationship between the claimant and the defendant so that he can be considered a claimant. If there is no indication of the validity of the claim, then how can he become a claimant such that the oath would be upon the defendant?

Benefits and Issues:
➊
The resolution of mutual disputes is based on testimony. In this, it is necessary for the witness to be trustworthy; therefore, it is essential to appoint witnesses at the time of buying and selling, especially when the transaction is valuable or the amount on credit is so large that there is a possibility of dispute regarding its payment or non-payment. Allah the Exalted has said:

“And appoint two men as witnesses from among your men. If two men are not available, then one man and two women from those whom you approve as witnesses.”

➋
When the claimant (plaintiff) is unable to present witnesses in a case, then an oath is taken from the defendant, and he will testify to the truth of his position by swearing by Allah.

➌
A decision cannot be made based on the claimant’s oath; for this, it is necessary to present witnesses.

Takhrij:
«أخرجه البخاري، التفسير، باب: ﴿إن الذين يشترون بعهد الله وأيما نهم ثمنًا قليلًا...﴾، حديث:4552، ومسلم، الأقضية، باب اليمين علي المدعي عليه، حديث:1711، وحديث البيهقي:8 /123، في سنده مسلم بن خالد الزنجي، وللحديث شواهدفهو حسن.»©Explanation:
In this hadith, an important principle of judicial decision-making is stated: the claimant (mudda‘i) must establish his claim with evidence and present two witnesses.
If he is unable to do so, then the defendant (mudda‘a alayh) will take an oath.
This is the position of the majority (jumhur) of scholars.