דבר שלא בא לעולם חלק ד - כסף שונה

1) A person can not sell something that does not yet exist in the world. It does not matter whether in a transaction, or as a gift, or as death-bed gift. For example, if he says, "What this field produces is sold to you," "What this tree produces is given to you," or, "Give whatever this animal births to Ploni," nothing has been acquired. And the same in all similar cases.

2) If someone sells the fruits of a tree to his fellow, he can renege on the deal, even after the fruits come into the world. And if the purchaser took them and ate, we don't make him give them back. And if either reneges, neither has to receive a "Mi Shepara"

3) However, if they agree to a transaction based on the market price, but seller didn't have the object in his possession, he must buy it, and give to the purchaser what they agreed. And if he reneges, he receives a "Mi Shepara."

Rav says : If someone is mekadesh a woman with a loan she is not mekudeshet, because loans are given to be spent.

She is not mekudeshet - even if the principal is still whole.

Given to be spent - The borrower is free to spend the money, and does not need to use it in a business such that it will be available at any moment until it is called. Since it is given to be spent, it is like it is hers, and he didn't give her anything.