The Biur Halacha notes that although it is forbidden to bow during
except at the points designated by Chazal, there is a custom to bow when reciting and responding to
. A precedent for this custom can be found in an incident in Tanach, when Dovid Hamelech urged everyone to bless Hashem (
) and the people fell to the floor and bowed. The Biur Halacha concludes, "
minhag Yisrael Torah
-Jewish customs are [authentic] Torah." Although the bowing mentioned in Tanach probably predates the prohibition against bowing at other points in
, it is unlikely that Chazal would have forbidden something that is clearly permitted by the
ביה"ל ד"ה הכורע; ביאורים ומוספים דרשו, 14)