1,672. Binding Verbal Commitments
Hilchos Ishus 23:13
Let’s say that a man asks his bride how much she’s bringing into the marriage and she gives him an amount, then she asks him how much he’ll give her (in the kesubah) and he replies with an amount, after which he betroths her. Their commitments are binding even though the couple did not perform an act of acquisition (kinyan). The same is true of a commitment made by a father for his son or daughter: if he is asked how much he’ll contribute on behalf of his son or his daughter and he names an amount, his word is binding. These are commitments that are binding based on one’s words alone.
Hilchos Ishus 23:14
The above applies when a father commits on behalf of a daughter – either a minor or an adult – or a son for their first marriage. A man feels a connection to his son and makes a commitment with words alone out of joy for his first marriage. However, if a brother commits money for his sister’s marriage, or a woman makes a commitment for her daughter, or other relatives commit money, or a father commits for his son or daughter’s second marriage – in all of these cases, the commitment isn’t binding until the one making it performs an act of acquisition (kinyan) stating the amount that he commits.