Rabbi Brown was a kashrus mashgiach (supervisor). He had once purchased blowtorch equipment for kashering ovens, which was useful during the Pesach season, but later accepted an administrative position and hadn’t used the equipment since.
A colleague, Rabbi Brenner, asked if he could buy the equipment. “I don’t want to sell the equipment at this point,” Rabbi Brown replied. “However, I’m happy to let you use it, provided that you take responsibility to return it in good condition should I need it again.”
Rabbi Brenner agreed, and they signed an agreement allowing him use of the equipment. Some time afterward, Rabbi Brown needed a kashering job done. He arranged with Rabbi Brenner to do the job without charge in lieu of the equipment.
The following year, Rabbi Brown notified Rabbi Brenner that his son just became a mashgiach. “I’d like the blowtorch equipment back,” he said.
“It’s mine now,” said Rabbi Brenner with surprise. “I did a job for you last year as payment for the equipment.”
“I never sold it to you,” said Rabbi Brown. “You agreed to do the job in return for having used the blowtorch during the past few years, a kind of rental compensation, but I never intended to sell it.”
“I was clear that the job was payment for buying the equipment,” replied Rabbi Brenner. “I don’t mean to be difficult, but it’s your word against mine. I’m in possession of the equipment, so if you want it back, the burden of the proof is now on you.”
“But I have proof,” said Rabbi Brown. “I have a signed contract that I lent you the equipment and you would return it should I need it again.”
“That’s irrelevant,” said Rabbi Brenner. “I acknowledge that you lent it to me, but claim that you sold it to me afterward. There’s no proof to negate that.”
“I see that we’re not getting anywhere,” said Rabbi Brown. “I suggest we consult Rabbi Dayan and let him decide.”
The two came before Rabbi Dayan. Rabbi Brown explained the circumstances and asked: “Does Rabbi Brenner have to return the blowtorch equipment?”
“When there are witnesses or clear evidence that a) Rabbi Brenner received the equipment as a loan and b) the equipment is still in his hand, he must return it,” ruled Rabbi Dayan.
“Why is that?” asked Rabbi Brenner. “What happened to the rule of hamotzi meichaveiro alav hareaya (the burden of the proof is on the plaintiff)?”
“The Gemara [B.M. 116a; B.B 46a, 52b] teaches that although the person currently in possession of an item usually has the upper hand, this does not apply to items that are lent or rented,” replied Rabbi Dayan. “In that case, the original owner is still considered the muchzak [in possession].”
“Why does there have to be evidence that the equipment is still in his hand?” asked Rabbi Brown.
“Otherwise, Rabbi Brenner has a migo that he returned the item,” replied Rabbi Dayan.
“Can you please clarify?” asked Rabbi Brown.
“As you know, there is a halachic concept of migo,” explained Rabbi Dayan. “When a person can make a winning claim, but instead claims something else questionable, he retains much of the rights of the winning claim. Simply stated, if the person were fabricating a lie anyway, he could have simply made the other, winning claim and won the case. This lends credence that his current claim is also true.”
“But how does that apply here?” asked Rabbi Brenner.
“In our case, if there were no evidence that the item was given as a loan, Rabbi Brenner could have claimed that he bought it from the outset and would have been believed,” explained Rabbi Dayan. “Additionally, if there were no evidence that the equipment was still in his hands, he could have claimed that he returned it already and would have been believed. Therefore, he would also be believed to say that he received the equipment as loan and later purchased it.”