Omissions from the prayer on Erev Yom Kippur:[1]

The following prayers are omitted on Erev Yom Kippur:

1. Tachanun
2. Lamnatzeiach
3. Mizmor Lesodah
4. Avinu Malkeinu.
5. Diminish in Selichos

A. Tachanun:[2]

Tachanun is omitted on Erev Yom Kippur.[3] It is not resumed until the 2nd day of Cheshvan.[4]

Is Tachanun recited by the Mincha prior to Erev Yom Kippur?[5] Tachanun is recited by Mincha of the 8th of Tishrei, which is the Mincha prior to Erev Yom Kippur.[6]

B. Lamnatzeiach:[11]

The psalm of Lamnatzeiach which is normally recited between Ashreiy and Uva Letziyon, is omitted on Erev Yom Kippur.[12] [According to Chabad custom, it is recited after Davening.[13]]

C. Mizmor Lesodah:[14]

The Psalm of Mizmor Lesodah which is normally recited after Baruch Sheamar, is omitted on Erev Yom Kippur.[15]

D. Avinu Malkeinu:[16]

Avinu Malkeinu is omitted both in Shacharis and Mincha of Erev Yom Kippur.

Erev Yom Kippur that falls on Friday:[17] Some[18] communities have the custom to say Avinu Malkeinu by Shacharis of Erev Yom Kippur in years that Yom Kippur falls out on Shabbos, in which case Avinu Malkeinu is not recited on Yom Kippur.[19] [Practically, the Chabad custom is to omit Avinu Malkeinu even when Erev Yom Kippur falls on Friday.[20]]

E. Diminish in Selichos:[21]

Those who recite Selichos during Aseres Yimei Teshuvah, diminish in the amount of Selichos recited on Erev Yom Kippur before Alos Hashachar. Some places however are accustomed to increase in Selichos prior to Alos being they do not consider it a Yom Tov at night and rather only from Alos and onwards. Practically, each place is to follow its custom. [The Chabad custom is not to recite Selichos at all during Aseres Yimei Teshuvah as explained in Chapter 1 Halacha 5B.]

______________________________________________________________________

[1] Admur 604:4-7

[2] Admur 604:4; Siddur Admur

[3] The reason: Although from the letter of the law Erev Yom Kippur is not a Yom Tov at all [and hence Tachanun should be recited], nevertheless the custom is to treat it like a Yom Tov. [Admur ibid]

[4] Siddur

[5] Admur 604:5; Siddur Admur; M”A 604:1; Levush 131:6; Kaf Hachaim 604:18; 584:74

[6] The reason: As the Yom Tov of Erev Yom Kippur is only accustomed to begin from nightfall even according to those opinions who view the night of Yom Kippur as a Yom Tov and thus decrease in Selichos and eat meat on the night of Erev Yom Kippur. [604:5]

[7] Based on Admur 604:3

[8] Hiskashrus footnote 15

^[9] Tzaruch Iyun on the above ruling in Hiskashrus as the Chabad custom is to never say Selichos during Aseres Yimeiy Teshuvah, hence what proof is there that we consider it a Yom Tov from the night as hold some opinions? To note that in the Siddur Admur writes that Kaparos is followed after Selichos, hence showing that Selichos is said at the night of Erev Yom Kippur. However, it is unclear if it is a normal amount of Selichos or a lesser amount.

[10] See Hiskashrus 948 footnote 48

^[11] Admur 604:6; Siddur Admur regarding all days that Tachanun is omitted; Rama 604:2

[12] The reason: As in this Psalm we mention “Liyom Tzarah” and Erev Yom Kippur is not a day of pain. [604:6; Levush 604:2]

^[13] Takana of Rebbe Rayatz, recorded in Siddur Tehillas Hashem prior to Musaf Davening of Shabbos.

[14] Admur 604:6; 1:17; 51:1; Siddur Admur; Rama 604:2

Other Opinions: There are opinions who hold that Mizmor Lesoda is recited on Erev Yom Kippur. [Kaf Hachaim 51:52]

[15] The reason for the omission: This is due to that the Toda sacrifice was not allowed to be brought on Erev Yom Kippur being that it diminishes its eating time. [Kama 1:17; 51:1] To note from Chidushei Tzemach Tzedek p. 208 who differentiates between Erev Yom Kippur and Erev Pesach, explaining the Toda offering was allowed to be brought on Erev Yom Kippur and hence Mizmor Lesoda should be recited. This concept of that the Toda was offered on Erev Yom Kippur is also accepted and defended by the Rebbe in Igros Kodesh 3 p. 71-72. Vetzaruch Iyun as why no mention was made of Admur’s clear ruling that the Todah was not brought.

^[16] Admur 604:7; Opinion in Rama 604:2 and custom of his city [of Krakow] “Regarding Avinu Malkeinu on Erev Yom Kippur, there is a dispute amongst the Achronim, and the custom of my city is only to say it when Yom Kippur falls on Shabbos, in which case Avinu Malkeinu is not recited, and we thus recite Avvinu Malkeinu by Shacharis of Erev Yom Kippur”; Rama 697:3 regaridng Mincha; Darkei Moshe 604:1 that so is custom of Krakow; Darkei Moshe 697:3 regarding Mincha; Hagaha in Minhagim 138; Mateh Moshe 835; Levush 604:2; Mateh Efraim 604:13; Luach Davar Beito; Luach Kolel Chabad; Luach Itim Lebina

Other opinions and custom of Sephardim: Some Poskim rule that Avinu Malkeinu is to be recited on Erev Yom Kippur. [Opinion in Rama ibid; Tashbeitz Katan 133, brought in Darkei Moshe 604:1] The custom of Sephardim is to recite it. [Luach Davar Beito]

[17] Admur ibid; Rama ibid; Darkei Moshe ibid; Mateh Moshe ibid; Levush 604:2

[18] Custom of Krakow, recorded in Rama ibid and Darkei Moshe ibid; Mateh Moshe ibid; Mateh Efraim 604:13 rules like this opinion; Minhag Karlin Stolin, brought in Koveitz Beis Yisrael Veaaronb

[19] See Admur 619:11 where it is explained that according to Ashkenazi custom, Avinu Malkeinu is not recited on Yom Kippur that falls on Shabbos

[20] Shevach Hamoadim 22:1 from Sefer Haminhagim [I have not found the source for this is Sefer Haminhagim]; Hiskashrus based on Luach Kolel Chabad. Otzer Minhagei Chabad 29 [To note that in Otzer Minhagei Chabad there is a typing error saying that the Chabad custom is to say Avinu Malkeinu when in truth their intent was to write that our custom is not to say it, as evident from the sources there.]

[21] Admur 604:4; Rama 604:2