Kavana - Concentration
“One must concentrate on the words and subject of each of the blessings of the Shemoneh Esrei. If this is too difficult, one should at least have concentration for the first blessing. If one did not say ‘Avot’, the first blessing, with proper intention, even if he said the rest of the blessings properly, he must still repeat the Shemoneh Esrei.” (Shulchan Aruch Orach Chaim 101:1)
The Rema writes that in our times one does not repeat the Shemoneh Esrei for lack of concentration, since it is likely that it will happen again.
Normally when there is a difference of opinion between Rabbi Yosef Karo, author of the Shulchan Aruch, and Rabbi Moshe Iserles (Rema), the Sefardim follow the ruling of the Shulchan Aruch while the Ashkenazim follow the ruling of the Rema. However, the Kaf HaChaim writes in the name of the Chida, one of the leading Sefardic halachic authorities, that in this case the minhag of the Sefardim is not like the Shulchan Aruch, and they as well do not repeat the blessing. (Birkei Yosef)
The Mishneh Berura explains that if one has not said Gd’s name at the end of the blessing, he can go back to “G-d of Avraham…” and repeat the blessing with proper concentration (according to Yalkut Yosef one goes back to “G-d of our Fathers…”).
The Importance of the First Blessing
The Avudraham explains that since the first blessing emphasizes
Considering the importance of the Shemoneh Esrei in general, and the first blessing in particular, one should take out time from his work or other learning in order to learn the meaning of the words he is saying, in addition to understanding the ideas contained in each of the blessings. In this way, each time he prays, his prayers will have increased merit. If it is too difficult to do this for all of the blessings, one should make a special effort for at least the first blessing.
- Recommended reading: The World of Prayer by Rabbi Eli Munk; Shemoneh Esrei by Rabbi Zev Leff; The Shemoneh Esrei by Rabbi Avraham Feuer