Reuven, Shimon, and Levi transferred to a new yeshiva and took over a nearby apartment previously occupied by Mr. Lewis. They arranged with Mr. Lewis to jointly buy some of the furniture that was in the apartment for $600.
A month after the three moved in, Mr. Lewis called Reuven. “You still owe me $600 for the furniture I left you,” he said.
“You’re right, I know,” apologized Reuven. “I’ll speak with Shimon and Levi and we’ll arrange to pay you immediately.”
That evening, Reuven told his apartment mates, “Mr. Lewis asked me for the $600.”
“What are you talking about?” Levi said. “We already paid Mr. Lewis for the furniture when we moved in!”
“No we didn’t,” said Reuven.
“I don’t think we did either,” agreed Shimon. “I know I never gave money for the furniture.”
“But I remember that we paid,” insisted Levi.
Reuven called Mr. Lewis again. “Are you sure we didn’t pay?” he asked. “One of the roommates claims we paid when we moved in.”
“I’m sure,” Mr. Lewis replied.
Reuven decided to turn to Rabbi Dayan. “Shimon and I are willing to pay the $400 we owe Mr. Lewis,” he told Rabbi Dayan, “but what about the remaining $200? Do we have to cover that too?”
Rabbi Dayan replied, “Partners who borrow or incur debt together are considered guarantors on the remainder of the loan or debt,” replied Rabbi Dayan. “Thus, if a lender or creditor cannot collect from one of the partners, he can collect the missing amount from the other partners [Choshen Mishpat 77:1].
“As you know, a person’s admission obligates him (hodaas baal din k’meah eidim dami), but it cannot obligate others. Thus, two partners who admit to a loan or debt become liable but cannot obligate a third party [Choshen Mishpat 77:5; 176:31]. They are, however, obligated to pay the third party’s portion as guarantors [Choshen Mishpat 37:4; Shach 77:12].
“It’s true that the halacha is that when the borrower is exempt, the guarantors are also exempt – so you and Shimon should seemingly be exempt – but since you claim Levi is liable, he is not considered exempt vis-à-vis you, and you remain liable to pay for his share [see Pischei Teshuvah 37:3; Ketzos HaChoshen 49:9; Aruch HaShulchan 37:18].
“One could argue that Levi should have to pay because two witnesses – you and Shimon – testify that he owes money, but your testimony is not believed because you have a vested interest in your testimony since if Levi owes money, you don’t [Sma 37:16].
“Thus,” concluded Rabbi Dayan, “the two people that admit that they owe money – you and Shimon – have to pay the full $600. You cannot obligate Levi to pay $200.”