Start with Lev 5:11. Do you often get blood from flour?
Then you can read the Stone Edition, page 555
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The Torah now lists offerings that are required in order to atone for sins, in contrast to the offerings of the previous chapters that one brings voluntarily in order to elevate oneself spiritually.
These offerings cannot atone for for sins that were committed intentionally. No offering is sufficient to remove the stain of such sinfulness; that can be done only through repentance and a change of the attitudes that made it possible for the transgressor to flout God's will. On the other hand, if the sin was committed accidentally and without intent, no offering is needed.
Sin offerings are needed to atone for deeds that were committed inadvertently, as a result of carelessness. As Ramban points out, even though they were unintentional, such deeds blemish the soul and require that it be purified, for if the sinner had sincerely regarded them with the proper gravity, the violations would not have occurred. As experience teaches, people are careful about things that matter to them, but tend to be careless about trivialities. Had the Sabbath, for example, been truly important to the inadvertent sinner, he would not have "forgotten" what day of the week it was. Had he been as scrupulous as he should have been about avoiding forbidden foods, he would not have carelessly confused forbidden fat with permitted fat.
This provides perspectives on the Torah's view of sin, it provides no "ritual" to atone for intentional sins, only God can see into man's heart and judge whether he has truly repented.Source: Sherman, R. Nosson et al (2004). The Chumash, Stone Edition. Menorah Publications, NY. Page 555. "
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So in the case of unintentional sins, a bloodless flour offering suffices.
In the case of intentional sins, a sacrifice won't do it.
Do you have any other insights into Judaism?
Here is some more stuff for you to gloss over
https://books.google.com/books?id=b1tG-zw2M-AC&pg=PA126&lpg=PA126&dq=source+tshuva+torah&source=bl&ots=hppr6WNRVt&sig=_xvXoXMNrNpg7Q3d7jpSSDw1DqU&hl=en&sa=X&ved=0ahUKEwjUt_Wdzp7PAhWH34MKHdE4DYEQ6AEIHjAA#v=onepage&q=source tshuva torah&f=false
Maybe some other time we can discuss your comments about human sacrifice and one man dying for the sins of another, 2 ideas which are alien to Judaism.