In our opening post on masechet Erachin we discussed how the use of the word hakol, everybody, comes to obligate one in a mitzvah, someone whom we might otherwise have exempted. We discussed no fewer than ten examples appearing on the first page alone.
Moving to the second page of the masechet, the Gemara continues on this same theme, where the use of the word hakol teaches that a minor who understands “to Whom we bless” may be counted in a zimmun after a meal; that women may (and as a matter of practical halacha, according to some authorities, must) form a zimmun if they have eaten together; that even infants are susceptible to tumah, impurity, and the laws of tzara’at; that children can declare an item hekdesh, dedicated for use in the Temple alone; that one who is uncircumcised may sprinkle the para adumah ashes to help purify those who are tameh; that a mumar, one who disregards mitzvot, can be a shochet; and that all in a household—including a slave—can demand that that family make aliyah to Israel and, once in Israel, can demand the family move to Jerusalem, even if that means living in a smaller apartment. “All” that in less than one page of Talmud.
After delineating the power of the word hakol, the Gemara wonders why so many rabbinic teachings, after stating that “hakol, all”, are obligated, specifically note that this includes kohanim, levi’im and yisraelim. As Rashi (Erachin 3b s.v. peshita) notes, “if they are not obligated, then who is?” Can one seriously entertain the possibility that “all” would not include kohanim, levi’im and yisraelim? Apparently, yes. The Gemara goes back and revisits the mitzvotof sukkah, tzitzit, tefillin, shofar, megillah, birchat hamazon and—ending where it all began, the mitzvah of erachin, the ostensible subject matter of our masechet—explaining why one might have thought that kohanim are exempt from the mitzvah and hence, the specific need to teach that kohanim are obligated in the mitzvah.
While, practically speaking, these possibilities are rejected, they teach much about the ideal way to perform a mitzvah. Despite the fact that kohanim may be unable to optimally do the mitzvah, they are nonetheless obligated in the mitzvah. Good may be the enemy of great, but better to do good than to do nothing. Please G-d in this post and next, we will discuss what we might learn from the specific mention of kohanim.
The mitzvah of sukkah requires that we make the sukkah our home for seven days, living in it as we would live in our home. The halacha demands that we bring our finest china and flatware to the sukkah. More fundamentally, we must live with our spouse during the festival, even more so than the rest of the year. Holiday time is time meant for family rejoicing. However, the chagim, especially Sukkot, which has the most elaborate Temple service of any of the holidays, is busy season for kohanim. Occupied in the Temple, they have little time to spend with family. Unable to spend time with their wives, one might have argued that they are exempt from the mitzvah of sukkah. And they would have been except for the fact, the Gemara explains, that the Temple service takes place during the day only, freeing them to spend the evening with their spouse. They are to be compared to travellers, who are exempt from the sukkah during their travels—i.e., in the day—but obligated in sukkah when they are resting, i.e., the night. Is it any wonder our Sages advised that, except under pressing circumstances, one should not work during chol hamoed?
The Torah juxtaposes the mitzvah of tzitzit to the prohibition of sha’atnez, the mixing of wool and linen, leading our Sages to teach that one may wear tzitzit even if the garment is made of linen and the fringes of wool, i.e., one is wearing sha’atnez. While a non-kohen may wear sha’atnez in his tzitzit, a kohen in the Temple is obligated to wear sha’atnez; the avnet, the belt worn by the kohen, was made of wool and linen. Had the Mishna not specifically noted that kohanim are obligated in tzitzit, one might have argued that only those who normally are prohibited from wearing sha’atnez must wear tzitzit, but those, i.e. kohanim, whose regular clothing consists of sha’atnez, need not too.
The mixing of linen and wool reflects the tension between the animal and vegetative kingdoms, a tension that melts away when performing the sacred services in the Temple, where G-d’s dominion over all is manifest. It is noteworthy that the korban tamid, the daily Temple sacrifice, consisted of a sheep, bread (wheat), oil (olives), and wine (grapes). Tzitzit are meant to induce a heightened awareness of G-d’s mastery over the heaven and earth, with the blue techelet serving to lift our thoughts and actions heavenward. One might have argued that the kohen, dressed in his divine clothing all day, has no need for tzitzit. However, our Sages assert such is not the case. When Temple service is over, he must don tzitzit; it is hard to maintain the aura of the Temple during “off-hours”.
Kohanim, our sages teach, are obligated in tefillin. That seems a rather obvious and superfluous teaching. But it is not. Kohanim are actually obligated only in tefillin shel rosh, but not tefillin shel yad. This is a result of the halacha which forbids any item to be placed between the kohen’s clothes and his skin. With a similar requirement regarding tefillin, something has to give; and it is the tefillin that must give way to the clothes of the kohen. With kohanim exempt from hand tefillin, one could very well have argued that there is little point to wearing tefillin shel rosh. One would not take a lulav without an etrog; so, too, there would seem to be little point to doing half the mitzvah of tefillin. While there are optimal and less optimal ways to do a mitzvah, one must do the whole mitzvah.
To this, the Gemara explains that, unlike the lulav and etrog that form one mitzvah, the two parts of the tefillin are actually separate mitzvot. With the hand symbolizing action, and the head our thoughts, our Sages understood that the two might not always be aligned. We may not be thinking about our relationship to G-d when performing mitzvot, and we may be doing mitzvot for ulterior motives, but the act of doing a mitzvah is of great value even if we are not fully engaged and focused on the mitzvah.
 Writing these words during the week of parshat Shelach Lecha, I cannot but compare the use of hakol, extending the reach of mitzvot, to another three-letter word: efes, “but”, one that caused the Jewish people to wander in the desert for 40 years. Language is a most powerful tool—please use it wisely.
 Most interestingly, the Gemara only explains the need to specifically mention kohanim. There is in actual fact no need to mention levi’im and yisraelim. The kohen derives his special status from his role of serving as the religious and civil servant of the Jewish people. In other words, if there are no levi’im and yisraelim, there is little need for kohanim.
 It is only in mitzvot between man and G-d that we invoke the principle of aseh doche lo ta’ase, a positive commandment overrides a negative. In mitzvot between man and man, violating a negative command in order to fulfill a positive one nullifies the mitzvah and makes one guilty of mitzvah haba b’averah, a [worthless] mitzvah accomplished through sin.
 Perhaps this can explain the reason tzitzit need not be worn at night. Night symbolizes the absence of divine presence. Only as the sunrise approaches, “when we can tell the difference between the white and the techelet” of tzitzit, does the obligation to recite shema and accept the yoke of heaven apply.