In the previous Halacha we have discussed the basic laws of bowing during the Amida prayer, i.e. at the beginning and end of the “Magen Avraham” and “Modim” blessings. We have likewise explained the proper way to bow. Let us now discuss whether or not the custom that many have to bend their knees while bowing is correct or if one should merely bow by bending one’s back and nodding one’s head.
Maran Ha’Shulchan Aruch (Chapter 113) writes: “When one bows, one should bow forward once quickly and when one straightens up, one should do so slowly by straightening one’s head first and then one’s body.” It seems according to this that when one bows, one should bow one’s body and head together and when straightening up, one should straighten one’s head first. Nevertheless, according to many Poskim including the saintly Ari z”l, one should not bow all at once; rather, while reciting the word “Baruch,” one should bow one’s body and while reciting the word “Ata,” one should bend one’s head. When straightening up, one should first straighten one’s body and only then one’s head. Some customarily behave in accordance with the ruling of Maran Ha’Shulchan Aruch while others follow the opinion of the Ari z”l.
The reasons behind this matter are lengthy and we cannot elaborate on them in the context of this Halacha.
According to all opinions though, when reciting Hashem’s name, one must be standing erect, as the verse states, “Hashem straightens the bent.” The Rishonim explain this to mean that before one recites the name of Hashem, one must already be standing erect as opposed to straightening up while reciting Hashem’s name.
Based on the above, it is clear that bending one’s knees while bowing is indeed unnecessary and bowing one’s body and bending one’s head are sufficient. Nevertheless, according to the Ashkenazi custom, while reciting the word “Baruch,” one should bend one’s knees and while reciting the word “Ata,” one should bow one’s body until one’s vertebrae protrude from one’s back (as we have explained in the previous Halacha). The custom of most Sephardic and Middle Eastern communities is not to bend one’s knees at all and one will bow his body until one’s vertebrae protrude already while reciting the word “Baruch.”
Upon reaching the “Modim” blessing, one should bow one’s body while reciting the words “Modim Anachnu Lach,” bend one’s head while reciting the words “She’ata Hu,” and straighten up before reciting the word “Hashem.”
Summary: When one reaches the blessings during which one must bow, one should bow one’s body and head together quickly while reciting the word “Baruch” (according to the Ari z”l, one should bow one’s body while reciting the word “Baruch” and bend one’s head while reciting the word “Ata”). According to the Ashkenazi custom, one should bend one’s knees slightly while reciting the word “Baruch,” bow one’s body and head while reciting the word “Ata” and then straighten one’s head and then body before reciting Hashem’s name. According to opinion of the Ari z”l, however, one should first straighten one’s body and only then one’s head according to both the Sephardic and Ashkenazi customs.