When Yisrael opened his garage on Friday morning, Eli was waiting there.

“I’m driving to Baltimore for Shabbos,” Eli said, “but funny things have been happening with the car recently. Can you check the battery and brakes?”

“Sure,” Yisrael told him. “Come back in two hours.”

Yisrael examined the car. The battery and brakes were fine, but there was a problem with the alternator. He tried calling Eli to ask whether to replace the alternator, but Eli was unavailable.

“It’s dangerous to drive to Baltimore like this,” Yisrael reasoned, “but if I wait until Eli returns, it will already be too late to order the part and install it.”

Yisrael ordered the alternator and began working. As he was finishing, Eli returned.

“I’m just about finished,” Yisrael said. “The battery and brakes were fine, but I had to replace the alternator. I tried reaching you, but you were not available.”

Eli looked uncomfortable. “Thank you,” he said, “but I didn’t want the alternator replaced!”

“But you needed it replaced,” said Yisrael. “It wasn’t safe to drive to Baltimore like this.”

“I only asked you to check the battery and brakes,” Eli insisted. “I didn’t ask for any other work and do not want to pay. If you want, you can put the old alternator back in.”

Yisrael rolled his eyes. “It’s already been opened and installed,” he said. “It’s not worth my time taking it out. But it’s not fair of you not to pay; the part was faulty and had to be replaced.”

“How you can do work without authorization and expect to be paid?” said Eli.

“I always ask, and did try reaching you,” Yisrael replied. “You were in such a rush this morning, though, that I was sure you would want me to fix whatever was necessary to get to Baltimore.”

“I can’t talk now,” said Eli, “but I’m willing to discuss this with Rabbi Dayan after Shabbos.”

“Agreed!” said Yisrael. “We can see him Sunday evening.”

The following week, Yisrael and Eli met with Rabbi Dayan. “I replaced a faulty alternator in Eli’s car before I had a chance to contact him,” Yisrael said. “He refuses to pay for the repair.”

“This case relates to an intricate topic called ‘yored l’sedei chaveiro shelo bir’shus,’ one who plants trees in another person’s field without authorization,” said Rabbi Dayan. “The Gemara (B.M. 101a) teaches that the owner has to pay if the work was beneficial. If the field was intended for trees, the owner has to pay to going rate for such work; if the field was not intended for trees, the owner pays a lesser amount (C.M. 375:1; SM”A 375:2).”

“What if the owner of the field says that he did not want the trees planted?” asked Eli.

“The Geonim rule that the owner can say that he does not want the trees,” replied Rabbi Dayan. “He can tell the planter to remove them and does not have to pay. There is a dispute, however, whether this applies also to a field intended for trees. The Shulchan Aruch indicates that he can say so even if the field was intended for trees, whereas the opinion of the Rama is unclear (C.M. 375:2,7; SM”A 375:4,14; and GR”A 375:2,17).

“The Chazon Ish (B.B. 2:3) explains that, in principle, everyone agrees that the owner does not have to pay if he truly does not want the trees,” continued Rabbi Dayan. “The dispute exists when the owner does not seem to have a valid reason: Is he simply looking for an excuse to evade fair payment for the benefit he received? The Aruch Hashulchan (375:11) suggests a similar rationale to explain the opinion of the Rama; it depends on whether he has a valid reason for not wanting the work.”

“But if it was dangerous to drive with the faulty alternator and it needed to be replaced,” asked Yisrael, “shouldn’t Eli have to pay for it?”

“The Rama rules that if someone repaired an abandoned house, the owner must pay him for essential repairs,” was the reply. “However, he can refuse to pay for repairs that were not essential and that he doesn’t want (375:7).

“Therefore, if the repair was essential for the car, Eli has to pay the going rate even if he did not ask for it to be done,” concluded Rabbi Dayan. “If the repair was not essential, but appropriate, it would be comparable to a field intended for trees that he can refuse to pay if he offers a valid reason.”

Q: I left some nails from a wood project on the sidewalk. They punctured the tires of a boy riding by on his bicycle. Am I liable for the tires?

A: Damage inflicted by any stationary obstacle, such as a nail, is included in the category of bor (pit). Whether the obstacle was placed there intentionally or through negligence, the person who created the obstacle remains liable, even if he disowned the obstacle and declared it hefker (C.M. 410:1; SM”A 412:9).

However, the Torah limits the legal liability of bor significantly, excluding damage to inanimate objects. There is legal liability only for injury or death of an animal or for permanent disability (nezek) to a person who was injured. Thus, there is no legal liability for the tires (C.M. 410:19-21; Aruch Hashulchan 410:26; Pischei Choshen, Nezikin, 7:[8]).

Nonetheless, the Gemara (B.K. 29a; 56a) indicates that the perpetrator is chayav b’dinei Shamayim for inanimate objects if he intended to damage. If he did not intend to damage, Rav S. Z. Auerbach, zt”l, maintains that there is no moral obligation (Minchas Shlomo, B.K. 29:4); the Chazon Ish remains doubtful; and Birkas Shmuel assumes that there is a chiyuv b’dinei Shamayim (P.C., Nezikin 1:[1]; 9:[53]).