Midrash su Levitico 23:28

1) (Vayikra 23:27) ("Only on the tenth day of this seventh month it is the day of atonement. A holy calling shall it be for you. And you shall afflict your souls and you shall present a fire-offering to the L–rd.") "the day of atonement, a holy calling," "the day of atonement and you shall afflict your souls," (Vayikra 23:28) "And all work you shall not do for it is a day of atonement." (Why three times?) For I might think that Yom Kippur does not atone unless he made it a holy calling (in the blessings of the day), and afflicted himself, and abstained from labor. Whence do I derive that even if he did not do these, the day atones? From "It is the day of atonement." I might think that Yom Kippur atoned only with the offerings and with the he-goats. Whence do I derive that the day atones even without them? From "It is the day of atonement." I might think that it atones both for those who repent and those who do not. — No would this follow? A sin-offering and a guilt-offering atone. Just as they atone only for penitents (viz. Bamidbar 5:7), so, Yom Kippur should atone only for penitents!

3) (Vayikra 23:28) ("And all work you shall not do on this self-same day; for it is a day of atonement to atone for you before the L–rd your G d.") "And all work you shall not do on this self-same day": This is the exhortation against labor (on Yom Kippur). (Vayikra 23:30) "And every soul that shall do any labor on this self-same day, I shall make that soul go lost from the midst of its people.": This is the punishment against labor.

8) I might think that there is no kareth liability for labor (on the addition), but that there is such liability for (non-) affliction on the addition; it is, therefore, written (Vayikra 23:29) "For every soul which will not be afflicted on this self-same day will be cut off." For (non-) affliction on the self-same day there is kareth liability, but not for (non-) affliction on the addition. I might think that he is not subject to the punishment, but that he is subject to (transgression of) the exhortation. It is, therefore, written "All work you shall not do on this self-same day." There is exhortation against (labor on) this self-same day, but not against labor on the addition.