וְכָל־הַנֶּ֗פֶשׁ אֲשֶׁ֤ר תַּעֲשֶׂה֙ כָּל־מְלָאכָ֔ה בְּעֶ֖צֶם הַיּ֣וֹם הַזֶּ֑ה וְהַֽאֲבַדְתִּ֛י אֶת־הַנֶּ֥פֶשׁ הַהִ֖וא מִקֶּ֥רֶב עַמָּֽהּ׃
Também toda alma que nesse dia fizer algum trabalho, eu a destruirei do meio do seu povo.
Rashi on Leviticus
והאבדתי I WILL DESTROY — This expression “destroying” is employed here because Scripture uses everywhere in similar cases the term כרת, “cutting off” without clearly defining it, so that I do not know exactly what it implies; but when it states here והאבדתי, it teaches in respect of the term כרת that it implies nothing else than becoming lost” (Sifra, Emor, Chapter 14 4).
Haamek Davar on Leviticus
I will cause that person to perish. This is more severe than the punishment for eating, and the reason is as the Seforno wrote: One who works on Yom Kippur does so out of spite, or he does not believe in the day’s holiness, whereas someone who eats does so out of desire.