The tenth day of every Hebrew calendar month of Tishrei is known as Yom Kippur, the Day of Atonement. The primary source of the holiness of that day comes from the historical account of the Torah, where Moshe, having ascended to Heaven to ensure forgiveness for the Jews for the sin of the golden calf, returns on Yom Kippur carrying the second set of Luchot [Tablets], intimating that the Jews had reached near-total exoneration for that blemish. Henceforth, the day of Yom Kippur was guaranteed as an eternal day of Atonement for the Jewish Nation. Based on this accounting, Rokeach writes [Parshat Emor], that the Holiday of Yom Kippur in fact eclipses that of Shavuot [the day the original set of Luchot (Tablets) were received], because the Tablets given on Shavuot were eventually destroyed by Moshe upon his witnessing the Jews frolicking around the golden calf. The National recovery of the Jewish people only concluded with the giving of the second Luchot on Yom Kippur many days later.
The highlight of the Yom Kippur service in the time of the Beit Hamikdash was the Kohein Gadol [High Priest] entering the Holy of Holies [Kodesh HaKadoshim], in special white garments, as the representative of the Jewish people. The Mishnah in Yoma [Perek 5 Halachah 2] offers, that this service was so sublime and awesome, that even angels were not allowed to be in the Holy of Holies during this service; it was the most intimate of moments between the man representing the Jewish Nation and Hashem Himself.
Interestingly, the Matteh Ephraim [chapter 610] comments that gold should not be worn on Yom Kippur, as since the Golden Calf was produced from gold, the “Defendant should not become the prosecutor [see Rosh Hashanah 26B].” There is a glaring issue with this comment, as the issue of the “Defendant” becoming the “Prosecutor” [in this instance the gold worn on Yom Kippur actually serving as a reminder about the golden calf] only applies to services performed in the Holy of Holies [hence the reason why the Kohein Gadol could not wear his typical golden garments on Yom Kippur]; why should a Jew praying in Shul also be bound by this concept?
The answer seems to lie in the Gemara in Rosh Hashanah 26B, which prohibits use of a cow’s horn on Rosh Hashanah, as in that case, the “Defendant” [the Shofar, which defends the merits of the Jews], will act as the Prosecutor, because it will remind G-d of the golden calf. The Gemara questions this assertion, as the Shofar is not blown inside the Holy of Holies, ergo, it should not be subject to this principle! The Gemara responds, that since the Shofar causes G-d to recall the merits of the Jews [as it were], the power of the Shofar is so holy, that it is considered as if those fulfilling that Mitzvah are actually in the Holy of Holies.
Based on this idea, the commentaries explain, that the prayers on Yom Kippur are so impactful, and of such a caliber, that the ones praying are considered equal to the Kohein Gadol, at the moment of his entering the Holy of Holies—therefore, the prohibition of wearing gold applies, for it is as if those prayers in fact are made directly in the presence of Hashem. It seems, that it is for this reason as well, that we chant the words “Baruch Sheim Kavod Malchuto Le’Olam Va’ed” out loud on Yom Kippur as well—something normally not done, for it can arouse the contempt of the angels who were the author of this prayer. For much like angels were not allowed in the presence of the Kohein Gadol during his time in the Holy of Holies [see the Yerushalmi quoted earlier], due to his purity and glory, so too, during our prayers on Yom Kippur, where we ascend to that level as well, the angelic prayer of “Baruch Sheim etc.” can be recited out loud, and we need not fear arousing the disdain of the angels for usurping their prayer.
[See the Gemara in Pesachim 56A, as well as the Tur Orach Chayim, Chapter 619].
May all our prayers be answered this Yom Kippur, and may Jewish Nation merit the coming of the Messiah speedily in our days.
Dedicated in memory of all those who have perished and sacrificed for Am Yisrael.
Have a Great Shabbas.