Kesubos 13:5-6

Kesubos 13:5

If a man agreed to give his son-in-law money as part of his daughter’s dowry but then he reneged, she can remain unmarried until her hair turns white (i.e., the groom is under no obligation to follow through with the wedding until the agreed-upon condition is met). Admon said that it’s fair to leave her in limbo if she fails to fulfill a condition but not if her father fails to fulfill a condition. In such a case, the groom must either marry her or release her. Rabban Gamliel agreed with Admon.

Kesubos 13:6

If a person contests the ownership of a field and he himself is a witness on the property’s bill of sale, Admon says he may still present his case. This is because it’s possible that he signed the bill of sale because he thought it would be easier to get his field back from the current possessor than from the one who sold it to him. The Sages say that if he signed the bill of sale, he can no longer contest the field’s ownership. If he sold another field abutting the one he is trying to claim, everyone agrees that he can no longer contest the field’s ownership.