Fact: While there was a real concern about the Kohen Gadol’s survival, there is no reference to this practice in the Mishnah, Talmud or Midrash. The Zohar does, however, state that a gold chain was tied to the Kohen Gadol’s ankle, but other sources, both halachic and Aggadic, could cause one to question this claim.
Background: :When the Beit Hamikdash was in existence, the highlight of the Yom Kippur service was the Kohen Gadol’sAvodah in the Kodesh Hakodashim. Twice during this exalted day, the Kohen Gadol would remove the eight priestly garments he wore during his service in the Beit Hamikdash all year long, immerse in a mikvah and don the four special white linen garments that were used only on Yom Kippur to enter the Kodesh Hakodashim. The rituals surrounding this entry, which are detailed in the Torah (Vayikra 16) and elaborated on by Chazal, had to be followed precisely. The slightest deviation could cost the Kohen Gadol his life (Vayikra 16:2). Indeed, many Kohanim Gedolim died during the Yom Kippur service (Yoma 5:1 [52b] with Rambam’s commentary; Tiferet Yisrael, Yoma, Yachin 22).
Owing to the danger, the Mishnah states that the Kohen Gadol would sponsor a feast upon emerging safely (Yoma 7:4 [70a]). According to the simple reading of the Mishnah (the peshat) (see Meiri, Yoma 7la), it would appear that the celebration was due to the Kohen Gadol’s safe emergence from the Holy of Holies. Rabbi Yisrael Kimchi (Avodat Yisrael, 1737, pp. 213a-214a), however, attributes the feast to the fact that the Kohen Gadol’s Avodah was accepted by God and the Jewish people were forgiven. During the later period of the Second Temple, the renegade Tzedukim (Sadducees) often succeeded in having members of their sect appointed as the Kohen Gadol. According to the Gemara (Yoma 8b-9a; 18a), the majority of the Kohanim Gedolim in the Second Temple period were ignorant and unworthy and bought their way to the position; some did, in fact, die on Yom Kippur. Only twelve Kohanim Gedolim served during the 410 years of the First Temple. In contrast, during the 420 years in which the Second Temple stood, there were four righteous Kohanim Gedolim, and more than 300 others who did not even serve a full year. It should be noted that although the Gemara says they did not serve an entire year, it does not specifically state that they died on Yom Kippur; while some definitely died then, others may have died under different circumstances or simply lost the position to a higher bidder.
If a Kohen Gadol died while in the Kodesh Hakodashim, his body had to be removed. Despite the usual restrictions upon entering various areas within the Beit Hamikdash, when a need arose, such as to remove tumah (an impurity), entry was permitted. The Tosefta (Kelim 1:11; cited in Eruvin 105a) explains that “all may enter [usually off-limit areas] to build or repair and to remove tumah. It is preferable that a Kohen enter, but if no Kohen is available, a Levite enters.  …” Although not explicit in the Tosefta, this leniency extended to the Kodesh Hakodashim (see Middot 4:5  and Rambam [Beit Habechirah 7:23]).
Chazal elaborate on these rules in their discussion of the sudden deaths of Nadav and Avihu, Aharon’s two sons. When they were killed within the mishkan (Vayikra 10:1-3), “lifnei Hashem,” Moshe requested their Levite cousins, Mishael and Eltzafan, retrieve the bodies (Vayikra 10:4-5). Tarat Kohanim cites a debate between Rabbi Eliezar and Rabbi Akiva about what transpired. Rabbi Eliezar says that an angel struck down Nadav and Avihu while they were in the Kodesh Hakodashim and then pushed them out to die in an area where a Levite may enter; subsequently, their Levite cousins removed their bodies. Rabbi Akiva opines that the phrase “lifnei Hashem” means they died within the Kodesh Hakodashim and the Levites removed the bodies by impaling them with iron spears and dragging them out. Hence, according to both accounts, the Levites did not enter the Kodesh Hakodashim to remove the bodies.
From all of the above, the following is clear: during the Second Temple period, especially, there was a particular concern regarding the Kohen Gadol dying and the permissibility of entering the Holy of Holies to retrieve his body. As it was preferable to avoid entering the sanctified area, the idea of tying a rope to the Kohen Gadol seems logical. However, it is somewhat puzzling that no source for such a rope is found in the Tanach, the Mishnah, the Talmud or in midrashei halachah. Rambam does not mention it in Yad Hachazakah  nor do any other Rishonim discuss it. It is not mentioned in the Ashkenazic Avodah piyyut “Amitz Koach” (circa tenth century) nor in the older Sephardic Avodah piyyut “Atah Konanta.” Moreover, it is worth noting that the rope is not mentioned in the Apocrypha, the Dead Sea Scrolls or the pseudepigrapha. Finally, one of the best eyewitnesses of Beit Hamikdash activities, Josephus, fails to note the existence of such a rope.
In contemporary Torah literature, the custom is mentioned in different sources with certain variations: it appears as a rope, a chain around the ankle and a chain around the waist. In most of these texts, no primary source is cited. Many modern sefarim refer to the custom as a “Talmudic tradition,” even though, as mentioned above, there is no Talmudic source for it. In the Zohar, however, the custom is mentioned twice. The Zohar on Parashat Acharei Mot (67a) describes the Kohen Gadol’s preparation before entering the Kodesh Hakodashim and states that “a gold chain was tied to his leg,” with no explanation or additional detail. In the Zohar on Parashat Emor (102a) the description of the Kohen Gadol’s entry into the Kodesh Hakodashim includes this statement: “Rav Yitzchak said: ‘One rope was tied to the Kohen’s leg when he went in, so that should he die there they could pull him out.’” 
Such a rope may have also served another purpose: to confirm whether the Kohen Gadol was dead or alive, since no one was allowed in the Beit Hamikdash throughout the duration of the Yom Kippur Avodah. Vayikra 16:17 states that no person could be in the Ohel Moed when the Kohen Gadol entered the Kodesh Hakodashim, and Chazal  understood this to be a prohibition on entering the Beit Hamikdash building-which applied to people and even to angels-while the Kohen Gadol was within the Holy of Holies.
While the existence of such a rope is widely thought to be true, there are several historical and halachic problems with it. The Gemara (Yoma 53b) relates that there was once a Kohen Gadol who recited a long prayer while in the Heichal (main sanctuary building). His fellow Kohanim assumed that he had died, and decided to enter the Heichal to look for him (obviously, the implication being there was no rope) On the way in they met the Kohen Gadol coming out and reprimanded him because, as stated in Yoma 5:1, he should not have prolonged his prayer in the Kodesh Hakodashim.
Rabbi Chiya relates (Yoma 19b) that once when a Tzeduki Kohen Gadol was still in the Heichal, those outside in the Azarah (Temple courtyard) heard a sound, and assumed that an angel had hit him in the face. They entered the Heichal and found him dead. Again, the implication is that there was no chain attached to this Kohen Gadol.
Furthermore, a gold chain around the Kohen’s leg can be a serious halachic problem. Rambam (Biat Mikdash 9:15) lists eighteen things that invalidate the Beit Hamikdash service, one of which is a Kohen who wears an extra “garment!” Such an act would not only invalidate the service, but a Kohen who thus performs the Avodah would incur death at the hands of Heaven (Rambam, Klei Hamikdash 10:4-5). Rambam, here, seems to imply (ibid.) that the prohibition is limited to wearing an extra layer of the standard priestly clothes. However, Rashi (Zevachim 18a, s.v., “yitur”), the Sifrei (Tzav 2:1) and Rambam elsewhere (Klei Hamikdash 10:8) imply that any extra garment or accessory can be problematic, and this is how the Aruch Hashulchan Ha’atid (Klei Hamikdash 31:7) understands the gemara’s conclusion (Zevachim 18a). For something to be considered an “extra garment;” it must measure at least 3x3 fingers in size or be something of significance (Aruch Hashulchan Ha’atid, Klei Hamikdash 31:14), for which a gold chain surely qualifies.
The placement of the suggested chain is also problematic. Even a speck of dust or an insect, is, ab initio, considered a chatzitzah (barrier) between the Kohen Gadol’s skin and his garments, invalidating his service (Rambam, Klei Hamikdash 10:7; Aruch Hashulchan Ha’atid, Klei Hamikdash 31:10). Thus, the chain could not be placed under his ketonet (robe), which extended until just above his ankle (Rambam, Klei Hamikdash 8:17). Presumably, the chain would have had to be tied on top of the Kohen Gadol’s robe, which would have impeded his ability to walk.
The Zohar’s suggestion of a gold chain, instead of a plain rope, is also perplexing. During his year-round service, the Kohen Gadol wore several vestments that included threads of gold or actual gold ornaments. However, on Yom Kippur, he entered the Kodesh Hakodashim in four simple garments of pure linen. This is because the custom is to not wear gold on Yom Kippur since “ein kataigor na’aseh sanegor, a prosecutor [the golden calf] cannot become a defense attorney [advocating on the Jew’s behalf]” (Rosh Hashanah 26a; Rashi, ibid., s.v. “ein kataigor”; Vayikra Rabbah 21:10). This is also why a bull’s horn may not be used for a shofar and why women do not wear gold jewelry on Yom Kippur (Rabbi Akiva Eiger, ShulchanAruch, DC 610, s.v., “yesh she’katvu”).
An additional problem relates to the tumah-transferring properties of gold. The purpose of the chain was to remove a dead body from within the Beit Hamikdash. While transporting the body, it would be logical to minimize the spread of tumat met (ritual impurity due to “contact” with the dead). Yet metals, unlike many other materials, acquire the same level of tumah as the actual dead body, thus rendering the Kohanim pulling on the chain tamei for seven days. Were an ordinary rope to be used, the Kohanim would only be tamei for one day, because a rope does not acquire the same level of tumah as a dead body.
Thus, there seem to be multiple problems with the notion of the Kohen Gadol wearing a gold ankle chain into the Kodesh Hakodashim. To recap: the chain may constitute an “extra garment”; the Gemara relates stories that indicate there was no rope used; gold is an unsuitable material to use for the removal of a dead body and is also inappropriate for use in the Kodesh Hakodashim; and such a chain would impede the Kohen Gadol’s functioning on a day in which he needs to perform the service optimally. Finally, an additional problem is that wearing a safety chain would seem to be an affront to the dignity of the Kohen Gadol.
Rabbi Uri Sherki, a rabbi in Kiryat Moshe, in Israel, suggests an allegorical interpretation of the “rope.” The Zohar, he says, is giving the Kohen Gadol a symbolic reminder that he should not get lost in the spiritual realm while performing the lofty Yom Kippur Avodah. One of the dangers associated with the high priesthood is that of getting too caught up in the spiritual realm and losing touch with this earthly world. In particular, the Kohen Gadol, upon entering the Kodesh Hakodashim on Yom Kippur, can become so overwhelmed by the spiritual that he is liable to “forget” to leave. The Zohar uses the imagery of a “rope” as a reminder to the Kohen Gadol that the Jewish people need him and he must “pull” himself back to this world after the extraordinary otherworldly experience of Yom Kippur.
In summation: Despite the paucity of rabbinic sources, the notion that the Kohen Gadol wore a rope around his ankle when entering the Kodesh Hakodashim is widespread. The historical evidence of such a rope or chain seems dubious and the halachic acceptability of such an arrangement is questionable. If such a rope was indeed used, it reflected the sorrowful state of affairs prevalent in the late Second Temple period, when so many Kohanim Gedolim were unworthy and therefore liable to perish in the Kodesh Hakodashim. May we be zocheh to soon see a worthy “unchained” Kohen Gadol perform the Yom Kippur service in his pure white garments in the rebuilt Beit Hamikdash.
1. I thank my wife, Dr. Naomi Zivotofsky, for pointing out that this hierarchy is not obvious with regard to removing a dead body, which a Kohen must avoid. Indeed, Chasdei David on the Tosefta suggests, without an explicit source, that this hierarchy applies to other forms of tumah but not to tumat met (ritual impurity due to “contact” with the dead).
2. These sources discuss entering the Kodesh Hakodashim in order to effect repairs or to remove tumah. But entry may be permitted for other needs. Ramban (Bamidbar 18:10), in a bold (re)interpretation of a sifrei (and Zevachim 63a), suggests that if the Beit Hamikdash is surrounded by enemies the verse gives permission to eat sacrificial meat and meal offerings in the Kodesh Hakodashim. Rabbi Shlomo Goren (Sefer Har Habayit, p. 405) explains that this exception refers to Jewish soldiers/defenders who are required to enter so as to continue to protect the Beit Hamikdash, and while inside may eat sacrificial meat and meal offerings.
3. I thank Dr. Yaakov Hoffman for bringing these sources to my attention.
4. The Malbim says if there had been a need to enter, Moshe would have charged the Kohanim with the task of retrieving them. Ramban and Tur explain that a Kohen takes precedence over a Levite regard to removing tumah from within the Kodesh Hakodashim, but in this case there was no Kohen who was permitted to enter, hence the Levites did the job.
5. This omission may not be so surprising to some, because they would expect Rambam to describe the pristine halachah only. This is not entirely correct because Rambam (Hilchot Yom Hakippurim 1:7) does mention the oath instituted because of the Tzedukim. During the Second Temple period, before performing the service, the Kohen Gadol had to take an oath that he would not alter any of the Yom Kippur procedures.
6. It should be noted that his discussion of the ritual of Yom Kippur (Antiquities, Book 3, sections 240-243) is quite brief. I thank Professor Louis Feldman for his assistance with Josephus.
7. This idea of a chain tied to the ankle has a parallel in the rabbinic corpus. In Kohelet Rabbah 9:8-9:10, it is reported that Rabbi Haggai was preparing to enter the tomb of Rabbi Hiyya Rabbah and there was concern that he might die within. He suggested, “Bring a rope and tie it to my leg. If I come out, good. If not, drag me out by my leg!” (He emerged alive and well.) Kohelet Rabbah is usually assumed to be a relatively late midrash, several hundred years post-Talmudic in composition. This source is noted by Rabbi Reuven Margaliot, Nitzotzei Zohar, Acharei Mot (Jerusalem, 5730).
8. This is translated and cited in Mishnat HaZohar, edited by Isaiah Tishby, vol. 2, p. 229.
9. As an aside, the Zohar proceeds to explain about the red thread that hung outside the Beit Hamikdash building; if it turned white, the Jewish people knew the Kohen Gadol was successful in obtaining God’s forgiveness for the nation; if it stayed red, they knew he was not.
10. Yerushalmi, Yoma 1:5; 5:2 (cited by Tosafot Yeshanim, Yoma 19b); Sukkah 4:6; Vayikra Rabbah 21:11-12.
11. See Ramban to Shemot 28:35 and Rabbi Meir Dan plotzki (1867-1928; Klei Chemdah, Tetzaveh, gimmel) regarding the “bells” on the Kohen Gadol’s coat on Yom Kippur.
12. Tosafot Yeshanim (based on Yerushalmi, Yoma 5:2) says that the Kohen Gadol was Shimon Hatzaddik, and it is thus possible that while a rope was usually used, in his case they deemed it unnecessary.
13. Of course, one could speculate that the chain was instituted subsequent to this story.
14. A gold chain can be justified by resorting to the Gemara’s (Rosh Hashanah 26a) explanation of why a gold kafu’machta (shovel and pan) were used. Only gold items through which the “sinner” glorifies himself are technically prohibited on Yom Kippur. Nonetheless, the use of a gold chain on Yom Kippur seems inappropriate.
15. I am suggesting that these gemaras contradict the Zohar’s description of a rope. Rabbi Yisrael Kimchi (Avodat Yisrael, pp.163b-165b) views the gemaras as posing strong questions on the Zohar, but he proposes two solutions: 1. The Talmud and the Zohar disagree about the permissibility of entering the Kodesh Hakodashim in case of an emergency. The Gemara understands that the Tosefta gives blanket approval to enter while the Zohar opines that, like the Torat Kohanim states with regard to Aharon’s sons, all efforts must be taken not to enter. Hence the Zohar requires a rope while the Gemara has no need for such ingenious solutions. 2. In an attempt to reconcile the Gemara and the Zohar he suggests a far-fetched interpretation of the Gemara, which is explained further in Avodat Yisrael.
16. See Yoma l0b for an example of where the Kohen Gadol’s dignity was taken into account.
17. Shiur from 3 Elul 5763, available at: http://ravsharki.org/content/view/1537/629/.
Reprinted from JEWISH ACTION Magazine, Fall 5770/2009 issue