After accepting Hashem’s dominion when reciting Shema Yisrael and mentioning many of the miracles that He performed for us as we left Egypt in the blessing of Emes V’Yatziv, we are now prepared for Shemoneh Esrei. Due to this heightened sense of awe, we should be afraid to speak lest our words fall short, and so we ask: “Hashem sefasai tiftach” – Hashem, open our lips (Abudaraham).
Most authorities rule that “Hashem sifasai tiftach” is a preface to Shemoneh Esrei, but not an actual part of it. Therefore, if one forgot to say it he does not need to repeat Shemoneh Esrei (Biur Halacha 111,2). Nonetheless, once a person has said, “Hashem sifasai tiftach,” he may not even answer amen (Mishna Berura 66,35).
When the shaliach tzibbur repeats Shemoneh Esrei he says, “Hashem sifasai tiftach” softly. This halacha holds true even if there are members of the congregation who are fulfilling their obligation to recite Shemoneh Esrei by listening to him. Since they are not verbalizing the words of tefilla and only listening to them, they need not hear this verse (Biur Halacha, ibid.).
Text Copyright © 2009 by Rabbi Daniel Travis and Torah.org