MISHNA: Only for the stack of wheat or barley - if it is wheat, [he pays for the] wheat; if it is barley -- barley.

If there was a goat tied to it ... he is liable - for the goat, since living creatures are also included [in the law of fire] by "or standing" [Exodus 22:5]. We do not exempt him [from payment] due to [the rule of] "he receives the greater [punishment]", since he is not liable to the death penalty on account of the [death of the] slave -- since he was not tied up, he should have escaped; therefore he is exempt from death and payment on [the slave's] account. But if the slave was tied up, he is exempt even for the goat and for the stack, since he is liable to the death penalty for the slave, as it is written: "this must be avenged" [Exodus 21:20]. "He receives the greater [punishment]" even if [the witnesses] did not warn him, so that he does not get executed; we have established that those who unwittingly [commit crimes that would cause them to be] liable to the death penalty are exempt [from monetary payments as well]. [Ketubot 34b:9] Regarding the goat, it makes no difference whether it is tied up or not; but once [the mishna] made the choice [of language] regarding the slave, it made the [parallel] choice [of language] regarding the goat. Another explanation is that the choice [of language] regarding the goat is also precise: if [the goat] is next to [the stack] he is exempt, since it should have escaped. This is what it is saying: if a slave was tied to it or if a goat was next to it, he is exempt. Even though it was explained at the end of the second chapter that "the ox is comparable to other property" [Bava Kamma 27a:11] and if one placed a coal on it and it burned, he is liable -- [that applies only] there, where he put it upon an ox, which was not expected to remove it. But here, [the goat] should have escaped.