1. May one repeat words in Davening?
Certain words and sentences of reference to Hashem are forbidden to be repeated in close proximity if it can be viewed that the repetition is for the sake of a second deity. Although in the Talmud and Shulchan Aruch only specific phrases of repetition are discussed, nevertheless it is understood from the Poskim that one must beware against doing so by any phrase that can be viewed with such connotation. This applies even if one is not in the midst of prayer. Furthermore, it is explained in Sefarim that during Davening it is improper to repeat any word even the above suspicion does not apply, as the dialect of the prayer was given an exact number of words and letters. In addition, if one is an area of prayer that it is forbidden to make an interval, then repeating words can constant making a forbidden interval.
In summary, repeating words in Davening can be problematic for three different reasons:
- It appears one is accepting a second deity.
- One is adding to the exact number of words said in prayer.
- One is making an interval in prayer.
The following is the law in Shulchan Aruch regarding the first issue. In the Q&A the 2nd and 3rd issues will be discussed:
It is initially forbidden to repeat Shema, whether one repeats word after word or sentence after sentence. It is even forbidden to read the entire paragraph and then repeat it a second time. It is however permitted to repeat Shema if a long interval takes place in-between the two recitations.
Obligation to protest against the repeater: One who repeats the Shema in Davening is to be hushed. This refers to one who repeats the entire verse, [meaning he says Shema until Echad and then repeats the sentence]. If however he simply repeats word by word [such as he says Shema, Shema; Yisrael, Yisrael], then although this is improper conduct, nonetheless there is no necessity to hush him. There are opinions however that rule to the contrary, that when one repeats word by word one is to hush him, and when he says the entire verse and then repeats it he is not to be hushed, although it is improper conduct. According to all however, the necessity to hush the repeater is only if he says it aloud before a congregation [and not when he is Davening in private with other people present]. Practically, those that repeat the verse of Shema Yisrael as is common done by Selichos and Neilah are to be taught not to do so, as according to all opinions it is considered improper conduct and according to some they must even be protested.
Repeating Shema by Kerias Shema Sheal Hamita: When reading the bedtime Shema it is permitted to read the Shema many times in a row, in order to fall asleep with the saying of Shema. However there is an opinion which rules that even by the bedtime Shema one is to beware not to repeat the first verse twice [although he may repeat from Veahavta]. Practically, one is to suspect for their opinion.
Repeating the first verse of Shema if one did not have Kavana the first time? If one did not have Kavana when he recited the verse of Shema then he must repeat the verse quietly if he is with a congregation, in order so it not appear as if he is accepting two deities. [If however he is in private then he may repeat the verse aloud.]
B. Repeating Baruch Sheim:
It is permitted to repeat the verse of “Baruch Sheim Kevod Malchuso Leolam Vaed” [when it is said after the verse of Shema]. The custom is to repeat “Baruch Sheim Kevod Malchuso Leolam Vaed” three times at the conclusion of Neila, after reciting Shema Yisrael.
One who repeats the word Modim, [i.e. he says Modim, Modim] is to be hushed, just as is the law regarding repeating Shema.
D. Repeating Hashem Hu Haelokim:
It is a valid custom to repeat the words “Hashem Hu Haelokim” seven times by Neila, as one is praising Hashem for dwelling above the seven heavens.
E. Repeating Amen:
Some Poskim rule one is to beware of repeating the word Amen in answer to a blessing, such as to say Amen- Amen. Other Poskim however rule it is permitted to do so, and so is the main ruling. This applies whether or not one repeats the Amen with a Vav [Amen Veamen] or without a Vav [Amen Amen].
One may not repeat words or sentences of reference to Hashem in close proximity if it can be viewed as if the repetition is for the sake of a second deity. This applies even if one is not in the midst of Davening. Hence it is forbidden to repeat the words of the verse of Shema, or Modim. It is however permitted to repeat the verse Hashem Hu Haelokim, and Baruch Sheim which is said after Shema, and one may answer Amen Amen. It is permitted to repeat all words and verses if some time has passed in-between.
In Davening: During Davening it is improper to repeat any word, even if it does not have connotation of a second deity, as explained in the Q&A below.
May one repeat Modeh Ani?
Seemingly one is not to repeat Modeh Ani unless an interval has occurred in-between.
May one repeat words in Davening if they do not connote a second deity?
No. During Davening it is improper to repeat any word, even if it does not have connotation of a second deity. The reason for this is because it constitutes an interval if one is found in an area of Davening in which an interval is forbidden. Furthermore, even if one is found in an area of Davening in which an interval is permitted, it is improper to repeat words of Davening, as the dialect of the prayer was given an exact number of words and letters.
Repetition due to lack of Kavana: The above applies even if one desires to repeat words due to lack of Kavana, and in such a case he is to think the words in his mind rather than verbalize them. Some Poskim however are lenient in such a case.
May the Chazan repeat words when singing a section of the Davening, as is common by Hallel and Chazaras Hashatz of Shabbos and Yom Tov?
No. The congregation is also to refrain from doing so when singing the prats together with the Chazan.
 So is understood from the fact the Gemara only mentions Modim and Shema, while Tosafus and the Poskim discuss the repetition of also other phrases, and whether it is allowed; So also rules Aruch Hashulchan 61/14 based on Rambam Shema 2/14 that it applies to all words and sentences. See also Igros Moshe 2/22
 61/8; Michaber 61/9; Brachos 33b
 The reason: As it appears as if he is poking fun at the prayer, and in certain instances it appears as if he is accepting upon himself two deities. [see footnotes below]
 Admur ibid; M”A 61/7; Thus those that repeat Shema in Selichos each time that they say Vayaavor, may do so without worry, as there is a long interval in-between.
The reason: As when there is a long interval in-between it does not appear as if one is accepting upon himself two deities. [ibid]
 Admur ibid; Gemara ibid
The reason: As it appears as if he is accepting upon himself two deities. [ibid; see Rashi on Gemara ibid]
 Admur ibid; Rashi ibid
The reason: As repeating word by word does not appear as if he is accepting upon himself two deities, but rather as if he is poking fun at the prayer. [ibid; Rashi ibid]
 Bahag in Tosafus Brachos 34a; Rif on Brachos ibid; Rambam 2/11
 Admur ibid; Tosafus 34a regarding congregation; Sefer Chassidim 18 and Taz 61/3 regarding quietly
 Admur 61/9; Michaber 61/11; Tosafus 34a
 Admur ibid; Michaber 61/10; Yerushalmi Brachos 1/1
 Mahariy Abuhav
 Admur 63/5; Taz 63/3; M”A 63/6; Sefer Chassidim 18; P”M 61 M”Z 3; M”B 61/22; Kaf Hachaim 61/34; See Kaf Hachaim 63/17
 P”M 61 M”Z 3; M”B 61/22; Kaf Hachaim 61/34
 Admur 61/12; Taz 61/4
 Seemingly however it is forbidden to repeat the verse of Baruch Sheim without first saying the verse of Shema. [Implication of Admur and Taz ibid brought in next footnote]
 The reason: Doing so does not appear like one is accepting two deities, as this worry is only applicable regarding Shema Yisrael which is the main part of Kabals Malchus Shamayim. However, once Shema has already been said one time there is no worry that repeating “Baruch Sheim Kevod Malchuso Leolam Vaed” appears like two deities, as it is being answered on the verse of Hashem Echad that was said in Shema Yisrael. [Admur ibid; Taz ibid] This however implies that to plainly say the Pasuk twice without having first said the verse of Shema is forbidden. On the other hand, perhaps everyone assumes that Baruch Sheim is going on Shema, even if they did not hear the person saying Shema, Vetzaruch Iyun.
 Admur ibid; 623/10
 121/2; Michaber 121/2; Mishneh Brachos 33b
 Admur 61/10; 623/10; Michaber 61/12; Tosafus Brachos 34a
 The repetition does not appear as if one is accepting upon himself two deities, as in the verse regarding Eliyahu [Melachim 1/18-39] it says “The entire nation proclaimed Hashem is Elokim, Hashem is Elokim.” [ibid]
 Admur 61/11; See M”A 61/10
 Rama 61/12; Ohel Moed brought in Beis Yosef
 The reason: As it appears one as if he is accepting upon himself two deities. [ibid]
 Beis Yosef 61
 The reason: As we find that David said “Amen Veamen” and there is no difference between one who says it with or without a Vav. [ibid; M”A ibid]
 Based on Aruch Hashulchan 61/14 and Rambam Shema 2/14 that the prohibition applies to all words and sentences.
 Rebbe in Toras Menachem 35/60; Ben Pras Yosef Toldos in name of Baal Shem Tov; Makor Chaim 61/11 “I have seen people repeat words 3-4 times and this is strange and very bad”; See Maharahm Shick 31; Piskeiy Teshuvos 51/6
 Tur 113 “My brother Rebbe Yechiel taught that Chassidei Ashkenaz would count and weigh the exact number of words in prayer and blessings.” See also Bach 51 that we repeat words in Az Yashir in order to have an exact number of Divine names in the prayer.
 Baal Shem Tov ibid; Piskeiy Teshuvos ibid
 See Ashel Avraham Butchach; Igara Deparka 62; Shulchan Hatahor 61/3-4; Piskeiy Teshuvos ibid footnote 56
 Rebbe ibid