Sa’if 9 Mechaber: Two persons lent money to one person or deposited an item in trust with that person. Only one of them then claims repayment of his part of the loan from the borrower or the return of the deposit. The borrower or the person with whom the item was deposited is under no obligation to repay any part of the loan or return the deposit to the sole plaintiff until the second lender or the second person who originally made the deposit joins in the claim together with the plaintiff.
If, however, the other lender or the other owner of the deposit is in town and is aware that the other lender or the other owner of the deposit has initiated a claim for the return of the money or the deposit and, despite knowing this, he does not join in the claim, then the defendant is obliged to return the entire loan or deposit to the sole plaintiff. If, however, the defendant tells the court he is prepared to pay the sole plaintiff his share of the loan or the deposit but would rather deposit the share of the lender or owner that did not join in the claim in escrow with the court rather than giving it in trust to the sole plaintiff, the court will allow him to do so.
Rama: The above ruling only applies in a situation where the two people who are now looking for the return of their money or deposit are the ones who originally lent the money to the defendant or deposited the item with him. The ruling would be different, however, in a case in which only one person originally lent the money or deposited the item with the defendant and that person subsequently died and was survived by two sons. If one of his sons claims his portion of the money or deposit, the defendant must give it to him and cannot withhold the money or the item until the other son joins in the claim.
Ner Eyal: The reason the defendant is entitled to refuse to repay the loan or to return the deposit to only one of its owners is that he accepted the money or the deposit from both. He must therefore repay the money or return the deposit in the presence of both. However, if it is clear the lender or owner of the deposit who does not join in the claim is aware of the fact that the claim is being made, the defendant may repay the entire loan or return the entire deposit. The reason for this is that the two lenders or the two owners of the deposit are partners in the transaction. From the fact that the other partner has not joined in the claim as co-plaintiff even though he knows about it, it can be presumed that he has authorized his partner as his agent to sue and collect on his behalf.
If on the other hand it is clear from the circumstances that the other partner or owner of the deposit is unaware that there is a suit against the defendant for the return of the loan or the deposit, the defendant has no authority to pay any money or return any part of the deposit to the sole plaintiff, including the money that part of the money or deposit that he received form that plaintiff. The reason is the same. Since the money was borrowed or the item was received in the presence of both owners, it must be returned in the presence of both owners. That does not mean the defendant can refuse to come to court and litigate with the sole plaintiff. He must come to court, but he has no authority to repay any money to the sole plaintiff or return the deposit unless both lenders and owners are present. There is another opinion, however, of the Shach, who maintains that even if the other partner is unaware of the claim, the defendant may pay the sole plaintiff his part if it is clear how much he is owed.