1) TWO DEATHS OR TWO KORBANOS
QUESTION: The Gemara says that Shmuel derives the concept of Chiluk Melachos (one who performs multiple Melachos on a single Shabbos is obligated to bring multiple Korbanos) from the verse "Mechaleleha Mos Yumas" -- "He who desecrates Shabbos shall die, he shall die" (Shemos 31:14), which implies that one who desecrates Shabbos is Chayav more than one death. According to Shmuel, this means that one is Chayav to bring more than one Korban for desecrating Shabbos inadvertently with multiple Melachos. The Gemara points out that even though the simple meaning of the verse is that he is Chayav more than one death for intentional desecration of Shabbos, we nevertheless learn about unintentional desecration of Shabbos from this verse, because there is another verse that teaches us the Chiyuv for intentional desecration of Shabbos.
Why does the Gemara need to prove that the verse does not refer to death for intentional desecration of Shabbos from the fact that there is another verse that teaches the same thing? Even without that proof, it logically cannot refer to intentional desecration of Shabbos, because a person cannot be punished with two deaths!
(a) TOSFOS (DH Im Eino) answers that if not for the other verse that teaches the punishment for one who intentionally transgresses, we would have thought that this verse teaches that one who intentionally transgresses a Melachah of Shabbos is punished with death, and it uses the expression "Mos Yumas" merely because that is the way that people speak (and it does not mean that one is punished with two deaths). The Gemara proves from the fact that another verse already teaches the Chiyuv Misah for intentional desecration of Shabbos that this verse refers to one who transgresses inadvertently, and the words "Mos Yumas" teach that there are multiple obligations for one who transgresses inadvertently (because it is possible to be Chayav to bring more than one Korban Chatas).
(b) The RITVA explains as follows. The Gemara in Sanhedrin teaches that when one has been sentenced to death by Sekilah and he flees when Beis Din attempts to execute him, Beis Din has the right to kill him in whatever way they can (for example, they may shoot arrows at him). Accordingly, we would have thought that the phrase "Mos Yumas" means that when one is Chayav Sekilah for intentionally desecrating Shabbos, he is punishable with two types of death. He is sentenced to die with Sekilah, but if he escapes, Beis Din may kill him in any other way. (Shmuel, who uses this verse to teach Chiluk Melachos, learns the Halachah in Sanhedrin from a different verse. See RASHASH and RAV ELAZAR MOSHE HA'LEVI HOROWITZ, who add that the verse cited by the Gemara here should be "Kol ha'Oseh Melachah... Mos Yumas" (Shemos 31:15) instead of "Mechaleleha Mos Yumas" (Shemos 31:14); see also RITVA.)
2) IF ONE FORGETS BOTH SHABBOS AND MELACHOS
OPINIONS: Rav Nachman and Rav Ashi argue about a case in which a person forgets both that it is Shabbos and that this act is forbidden on Shabbos. Rav Nachman says that he is Chayav to bring only one Korban, because it was his Ha'alamah (forgetting) of Shabbos that caused him to sin. Rav Ashi says that we must determine what his Ha'alamah was; if, when we tell him that today is Shabbos, he stops doing the Melachah, then he is Chayav to bring only one Korban (because his transgression was done due to He'elem Shabbos). If, when we tell him that the act he is doing is a Melachah, he stops doing the Melachah, then he is Chayav to bring a Korban for each Melachah that he did (He'elem Melachos).
In what manner does this determine what the person's Ha'alamah was?
(a) RASHI (DH Iy) explains that if he stops doing Melachah when we tell him that it is Shabbos, that shows that he was doing the Melachah with He'elem Shabbos, and thus he is Chayav to bring only one Korban. Similarly, if he stops doing the Melachah when we tell him that the Melachah is forbidden on Shabbos, that shows that he was doing the Melachah with He'elem Melachah, and thus he is Chayav to bring multiple Korbanos (a Korban for every Melachah that he performed).
(b) TOSFOS (DH Chazinan) quotes the RI and RASHBA who explain that the fact that the person stops doing Melachah when we tell him that today is Shabbos is not sufficient proof that he transgressed with He'elem Shabbos. Perhaps he also would have stopped had he told him that the act he is doing is a Melachah.
Rather, we must ask him, "Had we told you about the other aspect of your Ha'alamah (either Shabbos or Melachos), would you have stopped doing the Melachah?" If he says that "this factor caused me to stop doing the Melachah, but the other factor would not have caused me to stop," that is acceptable proof to determine what his Ha'alamah was, and, consequently, whether he is Chayav to bring one Korban or two.