2,632. Latching On to an Oath
Hilchos Shevuos 2:8
If person A heard person B take an oath and person A said, “I’m like him,” he isn’t liable because he neither made an oath nor had one imposed upon him. One is exempt for such latching on to an oath.
Hilchos Shevuos 2:9
Similarly, let’s say that a person took an oath saying, “I won’t eat this meat,” and he then said, “This bread is like the meat.” In such a case, he isn’t liable because of the bread since he didn’t take an explicit oath about it. Rather, he latched on to his oath about the meat. While he is exempt from lashes and from bringing an offering, it is nevertheless prohibited for him to eat the bread that he added on to his oath.