The Mishna on our daf discusses cases where someone claims to have married another person and the alleged spouse denies that the marriage had taken place. In cases where it is one person’s word against the other, the ruling is that the person who claims that the marriage took place cannot marry any of the other person’s immediate relatives (e.g. their alleged brother-in-law or sister-in-law), while the person who denies that the marriage took place can marry anyone – including immediate relatives of the alleged spouse.
The simple reason for this is because a Jewish marriage can only take place if there are appropriate witnesses who watch the exchange of money or contract that creates the marriage. Thus, even if both the husband and the wife agree that there was an exchange of a ring and that the woman accepted it with the full intention of getting married, according to Jewish law nothing of significance has taken place.
The reason for this is because halakha recognizes two distinct types of witnesses:
- An ordinary situation where the witnesses come to offer the information that they are privy to, and
- A unique situation, like marriage, where the witnesses are integral to the event.
Our Gemara does suggest that if there is a single witness and both parties agree that a marriage had taken place, that there is room to suggest that we must treat the kiddushin as marriage. The explanation for this possibility is that we do view business laws as one of the sources from which we derive the laws of marriage. In cases of business, a single witness is not ignored totally – as is the case in criminal law – in fact, while a single witness will not be relied upon to force someone to pay, his testimony will be enough to force the defendant to take an oath that he is telling the truth.