The wisdom behind this is that dealings involving property are among the most frequent of all transactions. If transactions involving marriage were compared to commercial transactions, sales would undoubtedly be far more numerous. Thus, out of Allah’s wisdom and mercy, He has broadened the forms of evidence accepted in financial matters, because people are so extensively involved in them.
His words, “two men, or one man and two women, or one man together with the claimant’s oath”: these are three types of evidence: two men; one man and two women; or one man together with the claimant’s oath. The proof is Allah’s saying:
“And bring to witness two witnesses from among your men. And if there are not two men, then a man and two women from those whom you accept as witnesses.” [al-Baqarah 2:282]
As for one man together with the claimant’s oath, this is established by the hadith of Ibn Abbas, may Allah be pleased with him: “The Prophet, peace and blessings be upon him, ruled on the basis of one witness and the claimant’s oath.” (1) The Messenger’s ruling, peace and blessings be upon him, is itself both a ruling and evidence, for he was a legislator, peace and blessings be upon him.
Should the witness be presented first, or should the oath be taken first? The witness is presented first. Thus, we say to the claimant: “Produce the witness.” Once he has testified, we say: “Swear an oath.” If he were to swear before producing the witness, it would not suffice. This is because, when he produces one witness, the required number of witnesses has not been completed; however, the claimant’s side is strengthened by producing that witness. Once his side is strengthened, the oath belongs to his side, because an oath is only prescribed for the side of the stronger of the two litigants. This is why it was previously mentioned regarding qasāmah that the oath is on the claimant’s side, because he possesses an evident circumstantial indication of his truthfulness. These, then, are three types of evidence, all of which establish a claim concerning property.