Shevuot 19A

דבעי למיכתב בהמה וחיה לכדרבי, כתיב נמי שרץ. כדתנא דבי רבי ישמעאל: כל פרשה שנאמרה ונשנית, לא נשנית אלא בשביל דבר שנתחדש בה.

the Torah needs to write both “domesticated animal” and “undomesticated animal” in the verse “or the carcass of a non-kosher undomesticated animal, or the carcass of a non-kosher domesticated animal” to teach that halakha that the school of R' Yehuda HaNasi taught (see 7a), “creeping animal” is also written, even though there is no novel element taught by the addition of that term. This is in accordance with what was taught in the school of R' Yishmael: Every passage in the Torah that was stated and repeated was repeated only for the novel element introduced therein. It is the style of the Torah to repeat an entire passage to teach even one additional halakha, in this case, that which was taught by R' Yehuda HaNasi.

ורבי אליעזר, האי ״בה״ מאי עביד ליה? פרט למתעסק.

The Talmud asks: And R' Eliezer, who maintains that in general it is not necessary that the unwitting transgressor know precisely which prohibition he violated, what does he do with the words “in which he sinned,” the words from which R' Yehoshua learned that there is no liability to bring an offering unless he knows precisely which sin he committed? The Talmud answers: According to R' Eliezer, these words emphasize the fact that one is liable only when he intends to do the prohibited act, to the exclusion of one who acts unawares and has no intention to perform the action. That is to say, if one was preoccupied with another matter and, acting unawares, he transgressed a prohibition, he is not liable to bring a sin-offering.