“Because on this day, He will atone you in order to purify you, from all of your sins before Hashem you will be purified,” (Vayikra 16:30).
It is written in the mishna in Yoma (88a) Yom Kippur atones for aveiros that were done against Hashem, but Yom Kippur doesn’t atone for aveiros done against people until one appeases the other person. Rabbi Elazar ben Azariyah derives this halacha from the pasuk, “Meekal chatto haaichem liphnai Hashem titahru—from all of your sins before Hashem, you will be purified.”
Zera Shimshon asks: What is Rabbi Elizar ben Azariah adding by deriving this halacha from a pasuk and not just from a sevarah, like the first opinion in the mishna?
He answers that since it is written in the mishna that Yom Kippur atones for aveiros done against people only when the wrongdoer appeases the other person, obviously, this wrongdoer knew that he did something wrong. If not, he wouldn’t even approach the other person to appease him. We can, therefore, infer from the fact that the Tanna Kamma compares aveiros done against Hashem to aveiros done against people and says that the only difference is if one has to appease the other party or not—that the case of aveiros done against Hashem is also speaking about a case when he was aware that he did something wrong. This being so, it would seem that the mishna is teaching that Yom Kippur atones only for an aveira done against Hashem when he is aware that he did something wrong. However, Yom Kippur does not atone if he never knew that he did something wrong or if he knew and when Yom Kippur arrived, he forgot about it.
Zera Shimshon explains that if this would be the case then the only difference between an “aveira bein adam laMakom” and an “aveiro bein adam lechavero” is that regarding an “aveira bein adam laMakom” in order for Yom Kippur to atone for it, one does not have to specify his aveira, while with regards to an aveira bein adam lechavero he needs to.
Rabbi Elazar ben Azariyah, therefore, quotes the pasuk, “meekal chattohaaichem liphnai Hashem titahru”—from all of your sins before Hashem, you will be purified to negate this possibility and to prove that on Yom Kippur, there is atonement for “aveiros bein adam laMakom”—whether he forgot that he did such an aveira or even if he never knew he did something wrong.
How do we see this in Rabbi Elazar ben Azariyah’s words?
First, a little background … The punishment for inadvertently committing an aveira—whose punishment is “kares”—when he commits it intentionally is that he brings a korban chattas. However, if he is not sure if he really did that aveira or not, he brings a different type of korban called an “asham talui,” which protects him from punishment as long as he is unsure if he sinned or not. If he finds later that he did indeed sin, he then brings a chattas. For instance, there are two types of fat in an animal which look the same, but one of them is prohibited to eat and it is called “chailev,” and the punishment for intentionally eating it is “kares.” The other type is called “shuman” and it is totally permitted to eat. In a case of two pieces of animal fat on a plate, where a person ate one of them thinking that they were both “shuman.” Later on, he found out that one of them was “chailev,” but he doesn’t know which one he ate—the “chailev” or the “shuman”—in such a case, he brings an asham talui. If he finds out later on that the piece of fat that he ate was, indeed, “chailev,” he then brings a chattas.
There is another difference between an asham talui and a chattas. When Yom Kippur falls out between the time a person did a questionable aveira and before he actually brought an asham talui, he is exempt from bringing the korban. However, if Yom Kippur falls out between the time a person was required to bring a chattas and when he actually brought it, he is required to bring the chattas. The Gemara in Krisos (25b) derives this difference from the phrase: “liphnai Hashem—before Hashem,” in the pasuk, “meekal chattohaaichem liphnai Hashem titahru—from all of your sins before Hashem, you will be purified,”—taking it to mean Yom Kippur only atones for sins that were made “liphnai Hashem—before Hashem,” that only Hashem knew about it and not if anyone else knew it.
Therefore—concludes Zera Shimshon—Rabbi Elazar ben Azariyah quoted the above pasuk, because if Yom Kippur would only atone for aveiros done against Hashem when they were known to the transgressor, it would contradict the above derasha in Krisos—that the pasuk is speaking of aveiros that are not known to anyone but Hashem. Therefore, it must be that even though it would seem that the Tana Kamma was speaking of aveiros known to the perpetrator, this cannot be true, and Yom Kippur atones even for sins committed against Hashem—even if the transgressor never knew about it or just forgot about it.