1) THE REASON FOR BURNING "TERUMAH TEME'AH"
QUESTION: The Mishnah (20b) states that one may not light the Shabbos candles with "oil that is burned." The Gemara (23b) explains that this refers to oil that is Terumah which became Tamei, which one is obligated to burn. It is called "burned oil" because there is a Mitzvah to burn it. The Gemara explains that one may not use it for the Shabbos candles because "since one is obligated to burn it, we are afraid that he might tilt the lamp (to speed up the burning process)."
RASHI (23b, DH she'Mitzvah Alav) explains that the reason why one must destroy Terumah that became Tamei is in order to prevent one from accidentally eating it (which is a severe Isur d'Oraisa).
RASHI here (25a, DH Mitzvah li'Serof), however, gives two reasons why one must burn Terumah Teme'ah -- "because it is similar to Kodshim that became Tamei (which must be burned), and, furthermore, in order to prevent [eating it by] accident." Why does Rashi give two reasons here, and only one reason earlier (on 23b)? (See BEIS HA'LEVI.)
(a) Earlier, the Gemara focused on why using such oil on Shabbos is prohibited. The Gemara said that the reason is because of the concern that one might tilt the lamp to hasten the burning process. There is no concern that one might tilt the lamp simply to perform a Mitzvah of burning the oil; only when there is a strong reason for someone to want to get rid of the oil do we worry that he might tilt the lamp. The strong reason why he would want to get rid of the oil is in order that he not accidentally transgress the severe prohibition of eating Terumah Teme'ah. That is why Rashi there emphasizes that the reason for burning the oil is to avoid accidental transgression.
Here, however, the Gemara is discussing the general source for burning Terumah Teme'ah. Therefore, Rashi gives both reasons. (M. KORNFELD)
(b) As we explained above, the Gemara (on 23b) gave the reason for why using such oil on Shabbos is prohibited -- it is because of the concern that one might tilt the lamp in order to get rid of the oil that could cause him to transgress a severe prohibition. The Gemara was not concerned with how one will get rid of the oil, but just that one wants to get rid of it. Therefore, Rashi there gives the reason why one would want to get rid of it.
Here, though, the Gemara is discussing the specific Mitzvah to burn the Terumah Teme'ah (how to get rid of it). What is the source for specifically burning Terumah Teme'ah (as opposed to using any other form of disposal)? The source for specifically burning Terumah Teme'ah is the law that requires Kodshim Teme'im to be burned. Therefore, Rashi mentions both reasons, one to explain why Terumah Teme'ah must be disposed of, and one to explain why it is specifically burned. (RAV YAAKOV D. HOMNICK in SEFER NACHALAS YAKOV)
2) THE SEVERITY OF DEATH AT THE HANDS OF HEAVEN
QUESTION: The Gemara says that one of the features of Terumah that makes it more severe than Kodshim is that one who eats Terumah while he is Tamei is punished with Misah b'Yedei Shamayim, while one who eats Kodshim while he is Tamei is punished only with Kares (early death and childlessness). Why is Misah b'Yedei Shamayim considered more severe than Kares, when Kares itself includes Misah? (Kares not only causes a person to die before his time, but it also causes him to die younger according to some, or to die childless according to others.)
ANSWER: When the Gemara mentions Misah, it is not referring to the punishment for eating Terumah while one is Tamei. Rather, as RASHI explains, it is referring to the punishment for a non-Kohen who eats Terumah. The punishment for a non-Kohen who eats Terumah is Misah b'Yedei Shamayim, while a non-Kohen who eats Kodshim is punished only with Malkus (Rambam, Hilchos Ma'aseh ha'Korbanos 11:8), and not with Misah or Kares. In this respect, Terumah is more severe than Kodshim. (TOSFOS to Yevamos 73b, DH she'Ken; see also Insights to Pesachim 32:2 and to Yevamos 73:2.)
3) WHO IS WEALTHY?
QUESTION: The Gemara presents four different views among the Tana'im as to the definition of "wealth." The Tana'im define it a number of ways:
1. A person who has "Nachas Ru'ach" from his wealth (he is happy with what he has, -Rashi) (Rebbi Meir)
2. A person with 100 vineyards, 100 fields, and 100 slaves to work them (Rebbi Tarfon)
3. A person who has a wife who does good deeds (Rebbi Akiva)
4. A person with a bathroom near his table (Rebbi Yosi)
What is the underlying point of their argument?
(a) According to RASHI the point in question is how much money a person should make it his goal to attain. (Apparently, the Tana'im are advising a person to work only until he has attained the prescribed amount, and then to retire and work no more.)
(b) The MAHARSHA explains that the first Tana (Rebbi Meir) emphasizes that money is worthless if one does not make use of it himself ("Nachas Ru'ach").
The other three Tana'im teach that it is futile to strive for wealth. If one's purpose is to become rich and famous (Rebbi Tarfon), regardless of how much he has he will always feel a need to attain more. If his goal is to earn money in order to provide for his wife and family, he would be better off marrying a woman whose needs are minimal and who does not make great demands of him (Rebbi Akiva). If he intends to save money so that he will be able to afford medical treatments when he becomes old and sick, he would be better off simply making it his practice to go to the bathroom immediately after every meal, and to accustom himself to other healthy practices (Rebbi Yosi).
(c) The words "poor" and "rich" are often used to refer to wealth and poverty in terms of Torah and Yir'as Hash-m (see Rashi, end of 33a). Rebbi Meir says that a person is considered a true Ben Torah and a G-d-fearing person if he is happy with whatever amount of wealth Hash-m granted him. One who displays content with his lot demonstrates complete trust in Hash-m.
Rebbi Tarfon explains that wealth is breadth of Torah knowledge. Grain produce ("100 fields") is a common metaphor for Halachic statements, while products of the vine ("100 vineyards") is a metaphor for Agadic statements (Vayikra 1:2; Sifri on "Dagan v'Tirosh"). The "100 servants to work them" refer to the large number of students who attend to the Rav and analyze every statement he makes.
Rebbi Akiva explains that the measure for achievement in Torah is how well-versed in Halachah a person is, and whether he practices what he preaches. A "wife" refers to the Torah that a person has learned (as in Mishlei 30; see Bava Metzia 84b and Rashi there, DH Haysah). A person's actions must be commensurate with his Torah knowledge.
Finally, Rebbi Yosi explains that wealth is measured by the ability to weed out flawed outlooks (Hashkafos) from one's mind, so that his material wealth (his "table," as in Berachos 5b) will not affect him adversely.
In short, the Tana'im are describing four different aspects of Torah wealth: wealth in emotion (Rebbi Meir), in speech (Rebbi Tarfon), in deed (Rebbi Akiva), and in thought (Rebbi Yosi). (M. KORNFELD)