The Mishnah in Yoma (18b) states that prior to Yom Kippur, the Kohen Gadol was administered an oath that he would not alter the Avodah (Service), and that that the elder Kohanim who administered the oath as well as the Kohen Gadol would then seclude themselves and cry. The Gemara (ibid. 19b) explains that the oath was necessitated by a concern that the Kohen Gadol was a Tzeduki (Sadducee) and that he would thus not perform the Avodas Ha-Ketores (Incense Service) as required by the Torah She-b’al Peh (Oral Torah law), which stipulates that the ketores must be ignited inside the Kodesh Ha-Kodoshim (Holy of Holies), rather than outside of it, as the Tzedukim sought to do. The Gemara further explains that the Kohen Gadol would cry because of the implied accusation that he was a Tzeduki and would thus seek to violate the rules of the Avodas Ha-Ketores, and that the elder Kohanim would cry because they had implicitly accused a righteous man.

The question arises as to why this particular oath precipitated tears, whereas other oaths throughout the Torah are not noted to evoke an emotional reaction. For example, the Torah requires a defendant who admits to owing only a portion of the amount claimed to take an oath that he does not owe the balance of the claim, and the Chachamim (Sages) imposed such an oath even upon a defendant who denies the entire claim – yet we have no record of anyone crying as a result of the implied accusation of fraud which comes along with the requirement to take these oaths. Similarly, a shomer (bailee) may be administered an oath as per the Halacha if the bailment is damaged or disappears under his watch – yet we find no cases of a shomer being brought to tears as a result of the administration of an oath, which carries an implication that he was dishonest and mishandled the bailment or was negligent with it.

Why does specifically the oath of the Kohen Gadol on Yom Kippur bring about tears, whereas other oaths do not?

The notion of the Kohen Gadol entering the Kodesh Ha-Kodoshim to seek atonement, while violating Halacha in the process by tampering with the Avodas Ha-Ketores, is the height of hypocrisy. To breach Torah law in the holiest place in the world, on the holiest day of the year, as part of a kapparah (atonement) process, is the epitome of quackery and phoniness. Thus, on a technical level, we easily see the difference between the circumstances of the Kohen Gadol’s oath versus that of other required oaths, for the implied accusation of utter hypocrisy which necessitates the Kohen Gadol’s oath is profoundly more severe and condemnatory than the implied accusations which precipitate other oaths in Halacha; hence, the great emotion involved with the administration of the Kohen Gadol’s oath.     

The goal and essence of Yom Kippur are self-evaluation and corrective introspection; the individual must confront himself and determine if his deeds and attitudes are in consonance with the Torah. Rather than ignoring his faults and continuing to go about as normal, acting as if he is conducting himself as he should and not giving second thoughts to his path in life, on Yom Kippur the individual is charged to look at himself in the mirror and see what he really is about. Yom Kippur calls on the person to subject himself to an honest analysis of the details and larger picture of his deeds and thoughts, such that he cannot escape from them and is forced to modify, correct and redo as need be.

This is the message of the Kohen Gadol’s oath. The oath defines what Yom Kippur is all about: will one be a hypocrite and continue in his misdeeds all the while he rushes through life as if he has no need to introspect, or will he subject himself to the yoke of Hashem’s expectations and confront himself with the truth about his life and that which needs to be corrected? The Kohen Gadol's oath reflects the very essence and goal of Yom Kippur, and the failure to recognize what Yom Kippur is about and proceed on a path of religious quackery is surely reason to cry.

It should be noted that the choice which the individual must make when he approaches Yom Kippur is symbolized by the Sh'nei Se'irim (Two Goats). The goats must be purchased together, appear identical and stand together with the Kohen Gadol as the Avodah begins, but they then depart for radically different destinies; one goat serves as a korban (sacrifice) whose blood enters the Kodesh Ha-Kodoshim and is applied to the most sanctified Mizbach Ha-Zahav (Golden Altar), while the other goat travels away to a very distant locus and crashes at the bottom of a cliff. The goats represent the individual, who stands at a crossroads on Yom Kippur and has the choice to engage in teshuvah (repentance), attain kapparah and become uniquely sanctified, similar to the Sa'ir LaShem (goat used for a korban), or to remove himself from the scene and avoid teshuvah  - yet he will ultimately end up in a spiritual crash, as exemplified by the Sa'ir Ha-Mishtale'ach (goat that is dispatched to the wilderness), which travels ever so far from the Mikdash when teshuvah and kapparah therein are about to occur. Both goats are initially identical, but they are assigned radically different, opposing destinations upon the Kohen Gadol's choosing of lots to determine their fates when the time for the kapparah of Yom Kippur approaches.

As Yom Kippur is about to set in, let us take advantage and engage in sincere introspection and thereby draw close to Hashem.