Mr. Samuel was having major renovations done to his house. His architect drafted detailed plans for the contractor, Reuven, who provided a clear estimate and a proper contract for the job.

As is the nature of construction, various modifications to the plans were implemented during the course of work. Reuven was careful to have these changes, with any additional cost, put down in writing and signed. However, one modification was not recorded but remained a verbal agreement. When the work was completed half a year later and final payment was being arranged, a dispute arose between Mr. Samuel and Reuven about the cost of that modification.

Both Mr. Samuel and Reuven were adamant that their recollection was correct. The amount in dispute was significant — $10,000 — and they could not reach a compromise. Reuven felt he had no recourse but to sue Mr. Samuel in a din Torah.

The two came to adjudicate before Rabbi Dayan’s beis din. Reuven stated his claim. “Ask anybody in the business,” he said. “The $15,000 price I gave Mr. Samuel was already a discount, and I can’t accept any less than we agreed upon.”

“The entire project was very substantial,” Mr. Samuel replied. “We agreed to have this modification done at cost, for $5,000.”

“Is there any sort of documentation?” Rabbi Dayan asked Reuven.

“Unfortunately, this one modification was agreed upon informally, so we have no documentation,” replied Reuven. “We were at the bris of Mr. Samuel’s nephew and were discussing the plans with his relatives. We agreed to this modification while sitting around the table.”

“Is there anyone who can testify about the agreement?” asked Rabbi Dayan.

“Mr. Samuel’s brother-in-law Rabbi Cohn was there,” said Reuven. “Mr. Samuel’s younger brother was also there. They clearly heard the amount; they even assured Mr. Samuel that it was a very good price! We can call on them to testify.”

“They’re relatives of mine, though,” Mr. Samuel pointed out.

“Do you expect Rabbi Cohn to lie?” asked Reuven. “He’s known as a man of impeccable honesty who wouldn’t lie for anything! Anyway, I understand that relatives can’t be trusted to testify on your behalf, but I’m calling on them to testify against you. Is there an issue with that?”

“Despite Rabbi Cohn’s impeccable reputation of integrity,” said Rabbi Dayan, “he is disqualified from serving as a witness, even to the detriment of his brother-in-law” (C.M. 33:3).

“Why is that?” asked Reuven.

“The Shulchan Aruch, based on the Rambam (Hil. Edus 13:15), establishes an important principle,” answered Rabbi Dayan. “He writes: ‘The fact that the Torah disqualified the testimony of relatives is not because they are presumed to love each other, since they are disqualified from testifying [for their relative] whether for his benefit or his detriment. Even Moshe and Aharon are not qualified to testify for each other. Rather, it is a gezeiras hakasuv (Scriptural decree)’” (C.M. 33:10).

“What does that mean?” asked Mr. Samuel.

“It means that the disqualification of relatives as witnesses is a procedural issue, not a question of honesty,” explained Rabbi Dayan. “Even relatives of the greatest integrity, such as Moshe and Aharon, may not serve as witnesses, and it makes no difference in whose interest they are testifying.

“Even so, I’m wondering if there is any way that we could call upon them to testify,” said Reuven. “I suspect that Mr. Samuel would accept Rabbi Cohn’s word as correct, regardless.”

“Although Rabbi Cohn is a disqualified witness,” answered Rabbi Dayan, “if Mr. Samuel is explicitly willing to accept him as a witness to testify against him, it is allowed. The acceptance should be confirmed through a kinyan sudar. This is done through having Mr. Samuel take a handkerchief or other item, as a symbolic gesture of committing himself to the outcome of his testimony” (C.M. 22:1).

“Thus,” concluded Rabbi Dayan, “Rabbi Cohn — despite his reputation of honesty — and Mr. Samuel’s brother cannot serve as witnesses, even to their relative’s detriment, unless Mr. Samuel explicitly agrees to accept their testimony as valid.”