“I can understand the car rental, since he paid money for it,” said Dov. “But why can’t I demand back the luggage carrier, which was just borrowed?”
“It is important to emphasize that a loan for a set time is a legally binding commitment,” explained Rabbi Dayan. “Even though Kalman borrowed the luggage carrier without any payment, he acquires legal right to use it for the stipulated time.” (C.M. 341:1)
“What if there was no stipulated time?” asked Dov.
“Then you could demand it back at any time,” replied Rabbi Dayan. “However, when the loan was for a set time, the commitment to lend for that time is binding.”
“So Kalman is believed just on his word alone?” asked Dov.
“In truth, since you contradict him definitively,” answered Rabbi Dayan, “he is required to swear a shevuas heses [rabbinic oath]. However, nowadays we avoid imposing oaths. In some cases, the beis din might seek a slight compromise in lieu of the heses oath.” (C.M. 73:2)