The Urim and the Tummim
Maimonides rules that the Urim and Thummim existed in the Second Holy Temple, however, the Holy Spirit of G-d did exist within them, and so they did not have the power to answer questions prophetically. He proves that they existed in the time of the Second Holy Temple because had they not existed, then the Kohen Gadol would have never been considered fully clothed because the Urim and Thumim are halachikly considered part of the eight holy vestments, which the High Priest must wear while performing the services in the Holy Temple. Maimonides writes that the Urim and Thumim, although present in the Second Holy Temple, did not perform they intended function because in order for one to receive a message through the Urim and Tumim, one must posses the "holy spirit", Ruach HaKodesh, which no one possessed during that time period. The Ra'avad, Rabbi Avraham ben David (1125-1198), argued with Maimonides on this point and felt that the Urim and Tummim were not essential components in the High Priest's holy garments. Therefore, according to the Raavad, it is possible that they did not exist in the times of the Second Holy Temple, because their absence does not disqualify the Kohen Gadol from performing the sacrificial services in the Holy Temple. The Raavad asked according to Maimonides who understood that the Urim and Tumim existed in the Second Holy Temple but they did not properly work because noone had Ruach HaKodesh, why does that Talmud list both the Urim V'Tumim and Ruach HaKodesh in the five elements which existed in the First Holy Temple but were absent in the Second. According to Maimonides, both the absence of the Urim V'Tumim and Ruach HaKodesh produced the same effect because the Urim V'Tumim were not actually, they merely did not function because of the lack of Ruach HaKodesh, so why then does the Talmud list the two separately? Perhaps one can answer that Maimonides employed a variant text of this Talmudic passage, which is consistent with the Midrashic parallel to this Talmudic passage that did not list the Urim and Tumim as part of the five things, which existed in the First Temple but not in the Second Temple.
Rabbi Yoseph Karo (1488-1575) explains the root of this dispute between the Rambam and Raavad. He explains that the Raavad understood that Urim VeThummim refer specifically to the parchment containing a special name of G-d, which was slipped into the folds of the Choshen breastplate. However, Maimonides understood that Urim VeThumim simply refers to the Choshen breastplate when used for divination. Therefore, Maimonides ruled that the Urim and Tummim were essential to the Kohanic garb, while the Raavad did not. Rabbi Shlomo Machlamah of Karlin explains that according to Maimonides, the term "Urim and Tummim" does not necessarily refer to the actual breastplate, but rather to the stones, which are adorned upon the breastplate. This is evident from the fact that Rabbi Karo attempts to prove Maimonides' stance against the Raavad that the Urim and Tummim existed in the Second Holy Temple from the Talmud, which records a story detailing how the Sages attempted to procure the required gems for the breastplate from a gentile whose father was asleep. Had Rabbi Karo meant literally that the breastplate itself was called Urim and Tummim, then from there would have not have needed to offer proof to Maimonides' view that the Urim and Tummim existed in the Second Holy Temple. Rather he must have understood that Maimonides learned that Urim and Tummim refer specifically to the precious stones, which adorned the golden breastplate. In fact, Rabbi Yechiel Michel Epstein (1829-1907) wrote that according to Maimonides the Urim and Tummim were the stones on the breastplate, while the Raavad understood like Rashi that the Urim and Tummim refer to the parchment containing the secret name of HaShem.
Indeed, Rashi understands like the Raavad that the Urim and Tummim were not essential components of the High Priest's dress. However, Rabbi Aryeh Leib Ginzburg of Metz (1700-1785) asked on this passage in Rashi that if the Urim and Tummim were not essential, then why the concept of Urim and Tummim was not used by the Talmud as the practical difference in an otherwise only seemingly theoretical dispute between Rabbi Yochanan and Reish Lakish. From here, Rabbi Ginzburg offered a proof to the view of Maimonides, against the opinion of Rashi and the Raavad. The view of Maimonides is also the view shared by the Tosafists and Rashi's own grandson, the Rashbam. According to Rabbi Yosef Karo, Maimonides holds that Urim and Tummim means the stones of the breastplate, while the Raavad understands that the Urim and Tummim refer to the parchment containing the holy name. However, why then does the Rashbam—who rules like Maimonides—explain like Rashi and the Raavad that the Urim and Tummim are the parchment with His name inscribed, instead of the jewels like Maimonides would explain and Maimonides' son, Rabbi Avraham ben Moshe (11850-1237), himself actually explained? This difficulty remains yet unanswered.
Rabbi Isser Zalman Meltzer (1870-1953) explains that even according to the understanding of the Raavad, it is possible that the Urim and Tummim did exist in the Second Holy Temple. He explains that perhaps the parchment with the Holy Name of G-d was indeed inserted into the Choshen even in the Second Holy Temple, but the Urim and Tummim produced no effect because Ruach HaKodesh did not exist during that time. Since the purpose of the Urim and Tummim was to be used as a means of communication with G-d, the lack of Ruach HaKodesh in the Second Holy Temple rendered the Urim and Tummim useless. This is because the raison d'etre of the Urim and Tummim are to "enlighten" people with G-d's messages. The Raavad was merely pointing out that this loss of the Urim and Tummim's purpose does not render the High Priest disqualified from service in the Holy Temple because of a lack of clothing. This is because there is nothing wrong with the physical Urim and Tummim, rather the spiritual level of the nation was so degenerate that Ruach HaKodesh did not exist, which technically rendered the Urim and Tummim useless. However, since the Ruach HaKodesh could have theoretically returned at any given time during the Second Holy Temple, had the nation's spiritual condition improved, then the Urim and Tummim were not totally considered lost. Nonetheless, the Talmud considered them lost during the age of the Second Holy Temple because in practice the Urim and Tummim did not perform their function.
The Raavad asked according to Maimonides, why the Talmud lists the absence of the Urim and Tummim and the absence of Ruach HaKodesh in the Second Holy Temple as two separate facts, if the former is really an outcome of the latter. Rabbi Yitzchok Zev Soloveitchik of Brisk (1886-1959) explained the opinion of Maimonides: He explains that the Talmud says that the Urim and Tummim ceased to function after the destruction of the First Holy Temple, while prophecy continued to exist until the deaths of Hagai, Zechariah, and Malachi, a few years after the construction of the Second Holy Temple. Therefore, assuming that Ruach HaKodesh is the same as prophecy, one can conclude that the Urim and Tummim stopped working before the cessation of prophecy. Therefore, it could not have been a direct result of the stoppage of prophecy. According to this, Rabbi Soloveitchik reconciles a seeming difficulty in the wording of Maimonides. Maimonides wrote that during the time of the Second Holy Temple, "the Urim and Tummim did not answer [questions] and they did not ask of the Urim and Tummim because there was no Ruach HaKodesh." Logically, one would have thought to place the fact that they did not ask of the Urim and Tummim before the fact that the Urim and Tummim did not answer any questions. However, Rabbi Soloveitchik explains that with the destruction of the First Holy Temple, the Urim and Tummim stopped working and even had someone asked it the Urim and Tummim a question, the Urim and Tummim would not have supplied an answer. Additionally, after the deaths of Hagai, Zechariah, and Malachi, when prophecy ceased, not only would the Urim and Tummim not supply an answer if asked a question, but no one fitting to ask a question to the Urim and Tummim lived because one needs Ruach HaKodesh to communicate with the Urim and Tummim, and at that time prophecy already ceased. Consequently, the cessation of the Urim and Tummim took place in two steps, which explains Maimonides' phraseology.
In this explanation, the Brisker Rov assumes that even during the time of the Second Holy Temple prophecy still existed until the deaths of Hagai, Zechariah, and Malachi. However, this assumption is not necessarily justified because Rashi understood that from the second year of the Persian King Darius II—the year that the Second Holy Temple was built—prophecy stopped. Rabbi Yaakov Emden explains that the source of this opinion of Rashi is a Talmudic passage, which states that Hagai, Zechariah, and Malachi prophesied in the second year of the reign of King Darius the Second. However, Rabbi Emden asks that there is Scriptural verse that explicitly refers to a vision shown to Zechariah in the fourth year of King Darius' reign, which implies that prophecy continued to exist even beyond the construction of the Second Holy Temple. Rabbi Meir Leibush ben Yechiel Michel Weiser (1809-1876) explains that in that one instance G-d spoke to a prophet even after the cessation of prophecy. This explanation has deep implication for the nature of prophecy in contemporary times, and implies that even after HaShem stopped prophecy, He might continue it. The simplest explanation, which the Brisker Rov probably understood in the opinion of Maimonides, is that explanation of Rabbi Yehuda Aryeh Leib Alter (1847-1905) who understood that prophecy continued in the time of the Second Holy Temple until the deaths of all previous prophets (i.e. Hagai, Zechariah, and Malachi). Thus, between the destruction of the First Holy Temple and the deaths of the trio of prophets, the Urim and Thomum stopped working, but Ruach HaKodesh maintained its existence.
Rabbi Meir Simcha of Dvinsk (1843-1926) offers a proof to the view of Maimonides based on an inference in a scriptural verse. The Torah describes "putting the Urim and Tummim into the Choshen". Rabbi Meir Simcha says that this implies that without the Urim and Tummim, the Choshen is viewed as incomplete, thus the Urim and Tummim must be a part of the Choshen and are necessary for the High Priest's garments. However, this is not necessarily a clear-cut confirmation of Maimonides' stance because Rabbi Yaakov Emden (1697-1776) infers the exact opposite from that self-same verse. Rabbi Emden understood that since the verse still refers to the Choshen as the Choshen even if it does not contain the Urim and Tummim, the Urim and Tummim must not be essential components of the Choshen, as the Raavad explained. Nonetheless, Rabbi Meir Simcha offers another proof to the position espoused by Maimonides from the Targum who referred to the wearing of the Urim and Tummim, which implies that they are a segment of the Priestly apparel worn by the High Priest.
Rabbi Usher Weiss explains the root of the dispute between Maimonides and the Raavad. Rabbi Yosef Ben Moshe Babad (1800-1874) writes that there was no Holy Ark created for the Second Holy Temple, because King Josiah already hid the Tablets that Moses received on Mount Sinai, and therefore, there was no need for the Ark of Covenant, which is merely meant to house the Torah Scrolls and Luchos tablets. Rabbi Asher Weiss explains that Maimonides understood that the relationship between the Choshen and the Urim V'Thumim is analogous to the relationship between the Aron HaKodesh and the Luchos. Just as when there are no tablets, there is no Ark, and then if there is no Urim V'Tumim then there is no Choshen, for its purpose is to house the Urim V'Tumim. Since the Choshen was surely one of the essential eight garments of the Kohen Gadol, then Maimonides had to explain that the Urim V'Tumim existed during the period of the Second Holy Temple. However, the Raavad understood that although the Ark served as a mere receptacle for the tablets, the golden breastplate did not serve as a vessel for holding the Urim V'Thumim. This is because the Torah calls the Ark, "The Ark of the Covenant" which implies that entire purpose of the Ark is to serve as a means of holding the covenant, which is physically represented by the tablets given to Moses on Mount Sinai. Nevertheless, the Torah never said concerning the breastplate that its entire purpose is to house the Urim V'Tumim, therefore, even without the Urim V'Tumim, the Choshen is still considered complete.
Rabbi Meir Simcha of Dvinsk explains that the Torah does not use the word Tamid, "continuously", in regarding to the wearing of the Choshen, as it does in regard to the wearing of the other garments because the Urim V'Tumim, a portion of the Choshen, were not used/did not exist during the period of the Second Holy Temple. He also explains that the Torah says, "It should be on the heart of Aaron", but does not say that Aaron should carry the Choshen on his heart. Perhaps one can explain this anomaly according to the Rabbi Asher Weiss' explanation that the Choshen was analogous to the Holy Ark. Since the carriers of the Ark did not actually carry the Ark, but the Ark rather carried them, perhaps the same can be true of the Choshen, that is, the Kohen Gadol did not carry the Choshen, and rather the Choshen carried itself upon the heart of the Kohen Gadol. Rabbi Simcha Meir himself explained that the Choshen is analogous to the tablets: Until the letters of the tablets flew up, Moses miraculously was able to hold onto the heavy slab of sapphire, but once the letters flew up, the weight of the object was too massive and he dropped it. The same is true concerning the Choshen; as long as the Choshen contained the Urim V'Tumim, the Choshen carried itself on the Kohen Gadol's chest, while after the Urim V'Tumim ceased to work or were gone, the High Priest had to actually wear the Choshen.
 Laws of the Beis HaBechirah 4:1 (The same is true according to Tosafos to Yoma 21b)
 See Maimonides, Laws of the Vessels of the Sanctuary 10:10
 Yoma 73b
 Hasagos HaRaacad to Laws of Bais HaBechira 4:1
 Yoma 21b
 See Midrash Tanchuma, Parshas Behaaloscha, End of §6
 Kesef Mishnah to Laws of Beis HaBechira 4:1
 Markeves HaMishnah to Laws of Beis HaBechira 4:1
 Kiddushin 41a
 Aruch HaShulchan HeUsid to Laws of Beis HaMikdash §8:15
 Exodus 28:30
 Yoma 5b
 Gevuras Ari to Yoma 5b
 Yoma 4b-5a
 See Chiddushei Maran HaGriz to Yoma 5b and Avi Ezri to Laws of Beis HaBechira 4:1 who proposes an alternate understanding to Rashi's of that Talmudic passage. Their explanation follows Tosafos Rid to Yoma 5b and according to their explanation, the Talmud in Yoma 5b does not refer to the Urim and Tummim and thus one can say like the Raavad that the Urim and Tummim are essential to the services. However, Rashi explicitly does not follow this explanation, so it is difficult to reconcile Rashi's opinion according to the Raavad, especially if one follows the Shulchan Aruch HaUsid who understood that Rashi and Raavad follow the same opinion.
 Tosafos to Yoma 21b
 To Bava Basra 133b
 See Rashi and Nachmanides to Exodus 28:30. This explanation is also quoted by Rabbi Yom Tov ben Avraham Ashevilli (1250-1330); see Chiddushei HaRitva to Yoma 73b.
 See the "Commentary of Rabbi Avraham ben HaRambam to the Torah" to Exodus 28:30
 Even HaEzel to Laws of Beis HaBechira 4:1
 See Brachos 4a which says that the word Urim comes from the word Ohr, meaning light
 Chiddushei Maran HaRiz HaLevi to Laws of the Vessels of the Sanctuary 10:10
 Sotah 48b
 Which Maimonides himself says in his Guide to the Perplexed, Chapter 42. However, Rabbeinu Bachaya argues on this point (see Rabbeinu Bachya to Leviticus 8:8) and he feels that Ruach HaKodesh is a lower level of divine inspiration, but is not prophecy.
 Laws of Beis HaBechira 4:1
 Yoma 21b
 Hagahos Ya'avetz to Yoma 21b
 Megillah 15a
 Zechariah 7:1
 Malbim, Gayah Chazayon, to Zechariah 7:1
 Sfas Emes to Yoma 21b
 Ohr Somayach to Laws of Beis HaBechirah 4:1
 Leviticus 8:8
 Hagahos Ya'avetz to Yoma 21b
 See Targum Yonason ben Uziel and Targum Onkelos to Deuteronomy 33:8
 Minchas Usher/Minchas Asher to Bava Basra §60:8
 Minchas Chinuch, Commandment #95
 Exodus 30:7, see Rashi there
 Although Rabbi Asher Weiss questions whether this explanation can fit with Rashi to Exodus 28:30 who explained that the breastplate is referred to as the Choshen Mishpat because of the divination powers of the Urim V'Tumim, which can serve as a jury to rule judicial cases fairly.
 Meshech Chochmah to Exodus 28:30
 See Sotah 35a
 Pesachim 87b