The Body in Prayer

(י) כָּ֥ל עַצְמוֹתַ֨י ׀ תֹּאמַרְנָה֮ יהוה מִ֥י כָ֫מ֥וֹךָ מַצִּ֣יל עָ֭נִי מֵחָזָ֣ק מִמֶּ֑נּוּ וְעָנִ֥י וְ֝אֶבְי֗וֹן מִגֹּזְלֽוֹ׃

(10) All my bones shall say, “YHWH, who is like You? You save the poor from one stronger than him, the poor and needy from his despoiler.”

Midrash Tehillim (12th c.)
With my head, I bend my head and bow down in prayer…And I also wear tefillin on my head. With my neck, I fulfill the precept of wrapping oneself in tzizit. With my mouth, I praise You, as it says: “My mouth shall speak the praise of the Lord” (Ps. 145:21)…With my face, I prostrate myself, as it says: “He fell down on his face to the earth” (Gen 45:12)… With my nose, when I smell spices with it at the outgoing of Shabbat. With my ears, I listen to the singing of the Torah.
Brachot

א רבי בא בריה דר' חייא בר אבא אכל מהלך עומד ומברך. אכל עומד יושב ומברך. אכל יושב מיסב ומברך. אכל מיסב מתעטף ומברך. אם עשה כן הרי הוא כמלאכי השרת.

Rabbi Ba son of Rabbi Chiyya son of Aba teaches: If one ate while walking, he must stand and bless. If one ate while standing, he must sit and bless. If one ate while sitting, he must recline and bless. If one ate while reclining he must enwrap himself and bless. If he did this, he is like the ministering angels.

Bowing, Kneeling and Prostrating

(ה) רֽוֹמְמ֡וּ יהוה אֱלֹהֵ֗ינוּ וְֽ֭הִשְׁתַּחֲווּ לַהֲדֹ֥ם רַגְלָ֗יו קָד֥וֹשׁ הֽוּא׃(ט) רֽוֹמְמ֡וּ יהוה אֱלֹהֵ֗ינוּ וְ֭הִֽשְׁתַּחֲווּ לְהַ֣ר קָדְשׁ֑וֹ כִּֽי־קָ֝ד֗וֹשׁ יהוה אֱלֹהֵֽינוּ׃

(5) Exalt YHWH our God and bow down to His footstool; He is holy!...(9) Exalt the YHWH our God, and bow toward His holy hill, for the YHWH our God is holy.

(יא) אלו ברכות ששוחין בהן ברכה ראשונה תחלה וסוף ובמודים תחלה וסוף והשוחה בכל ברכה וברכה מלמדין אותו שלא ישחה

(11) In these Berachot (blessings) we bow down: the first Beracha (blessing) [of Shemoneh Esreh], in the beginning and at the end, and in [the paragraph of] Modim [in Shemoneh Esreh], in the beginning and at the end. And [as for] one who bows down in every [single] Beracha [of Shemoneh Esreh], we teach him that he should not bow down [in them].

תניא אמר רבי יהודה כך היה מנהגו של רבי עקיבא כשהיה מתפלל עם הציבור היה מקצר ועולה מפני טורח צבור וכשהיה מתפלל בינו לבין עצמו אדם מניחו בזוית זו ומוצאו בזוית אחרת וכל כך למה מפני כריעות והשתחויות:

It was taught in a baraita that Rabbi Yehuda said: This was the custom of Rabbi Akiva, when he would pray with the congregation he would shorten his prayer and go up, due to his desire to avoid being a burden on the congregation.But when he prayed by himselfa person would leave Rabbi Akiva alone in one corner of the study hall and later find him still praying in another corner. And why would Rabbi Akiva move about so much? Because of his bows and prostrations.

ת"ר קידה על אפים וכן הוא אומר (מלכים א א, לא) ותקד בת שבע אפים ארץ כריעה על ברכים וכן הוא אומר (מלכים א ח, נד) מכרוע על ברכיו השתחואה זו פישוט ידים ורגלים וכן אומר (בראשית לז, י) הבוא נבוא אני ואמך ואחיך להשתחות לך ארצה:

The Sages taught: The term kidda indicates falling upon one’s face...Keria means descending upon one’s knees...Hishtaḥava’a, this is prostrating oneself while spreading one’s arms and legs in total submission.

אמר רבי תנחום אמר רבי יהושע בן לוי כנגד שמונה עשרה חוליות שבשדרהואמר רבי תנחום אמר רבי יהושע בן לוי המתפלל צריך שיכרע עד שיתפקקו כל חוליות שבשדרהעולא אמר עד כדי שיראה איסר כנגד לבו רבי חנינא אמר כיון שנענע ראשו שוב אינו צריך אמר רבא והוא דמצער נפשיה ומחזי כמאן דכרע

Rabbi Tanḥum said that Rabbi Yehoshua ben Levi said: In those blessings where one is required to bow, one who prays must bow until all the vertebrae in the spine protrude.Establishing a different indicator to determine when he has bowed sufficiently, Ulla said: Until he can see a small coin [issar], on the ground before him opposite his heart (Rav Hai Gaon). Rabbi Ḥanina said: There is room for leniency; once he moves his head forward, he need not bow any further. Rava said: But that applies only if he is exerting himself when doing so, and he appears like one who is bowing.

Avram ben Maimuni (1186-1237), Responsum 62
1) Teach us, rabbi, if it is forbidden, or worthy to prevent (full prostration in prayer), lest he seems as if he is violating the laws of the sages, or whether one should not prevent (prostration) since it is the pathway of awe and service in extra intention (kavannah), and our sages didn’t prevent us from that. 2) From this you learn that anything that increases the intention (kavannah) of the heart in prayer is praiseworthy and esteemed. 3) The reason that the sages required bowings at the beginning and the end of the amidah was to say that one should not do less than this, but not to forbid one from doing more than this. Know that this was done in order to be lenient on the community which doesn’t have the strength to do more than this. 4) When (the baraita) says, “You teach him not to bow,” it means, you teach him that he doesn’t have to bow, lest he make a mistake and thinks that he must bow more. 5) If you claim that (prostration) is forbidden because the non-Jews or the Karaites pray this way, we respond by saying: The Christians pray toward Jerusalem, and that doesn’t forbid us from praying toward Jerusalem. The non-Jews stand in prayer, and we stand. They bow just like we bow.
Shuckling (for Torah and Tefilah)
Zohar, Bamidbar 218b-219a
The souls of Israel are derived from the Holy Lamp [of God]...When a Jew utters one word of Torah, the light [in his soul] is kindled…and he sways to and fro like the flame of a candle.
Rabbi Simhah of Vitry (France, d. 1105)
[Young children are taught to sway when they study the Torah, "for thus we find at the giving of the Torah 'And the people saw and they trembled' (Exodus 20:15)".

ונהגו המדקדקים להתנועע בשעה שקורין בתורה דוגמת התורה שנתנה ברתת וכן בשעה שמתפללים על שם כל עצמותי תאמרנה יהוה מי כמוך [אבודרהם]:

And those who are exacting have practiced to shake at the time that we read the Torah as an illustration of the Torah that was given with trembling, and so too at the time that we pray, because of "all my bones will say to you, Lord who is like You?" (Abudarham)

Rabbi Abraham of Lunel (Toledo, d. 1215)
A person is required to sway during prayer, as it is written: "all my bones shall proclaim: O God, who is like You!" (Psalms 35:10)...And this is the custom of the Rabbis of France and her pious ones.

(ג) כתב רבינו הרמ"א דנהגו המדקדקים להתנועע בשעה שקורין בתורה, דוגמת התורה שניתנה ברתת. וכן בשעה שמתפללים, על שם "כל עצמותי תאמרנה...". עד כאן לשונו. והתורה נקראת "אש", והאש תמיד מתנועע. ובתפילת שמונה עשרה יש מתנועעים ויש שאינם מתנועעים. ותלוי לפי טבעו, דאם בהתנועע הכוונה יותר טוב אצלו – נכון להתנועע. ויש אדם שכוונתו יותר ברורה כשעומד בשווה לגמרי לא יתנועע. והכל לשם שמים. ובזוהר יש למה ישראל מתנענעים, עיין שם בפינחס דף רי"ח ע"ב טעם נכבד בזה.

R. Yehiel Michal Epstein (d. 1908)

And during the Amidah there are some who sway and some who don't and it depends on the person's nature. If by swaying, his kavanah improves, then he should sway; and a person whose kavanah is clearer when he stands perfectly still should not sway - and [either option] should be done for the sake of heaven...

Prayer is union with the Shechina. Just as two people will move their bodies back and forth as they begin the act of love, so must a person accompany the beginning of prayer with the rhythmic swaying of the body. But as one reaches the heights of union with the Shechina, the movement of the body ceases.

Baal Shem Tov
When a person is drowning in a river and he makes movements in order to extricate himself from the water, those who see him will no doubt laugh at him and at his motions. Thus, when a person prays and makes motions, one should not laugh at him because he is saving himself from the malicious waters which are the. . . foreign thoughts which come to distract him during prayer.