Even when a person’s head is clear of other thoughts, he cannot say that he is concentrating on his prayers. He must also try and ponder the meaning of the words that he is saying, and at the same time enter the mindset of actually conversing with the Creator of the universe.
A person should try to think about the meaning of the words that he is saying during the duration of the Shemoneh Esrei. If he is unable to do this, he should at least concentrate on the meaning of the words during the first berachah (Berachos 34b, Shulchan Aruch 101,1).
Some authorities write that if a person did not perceive himself as standing in front of Hashem for the entirety of his tefillah, he has not fulfilled his obligation (Rav Chaim Brisker on the Rambam, Hilchos Tefillah). Although this is certainly a worthy goal, the halachah is that one fulfills his obligation of tefillah even if he didn’t manage to retain this mindset for the duration of the whole Shemoneh Esrei.
Text Copyright © 2013 by Rabbi Daniel Travis and Torah.org