Tefillah is one of the most essential parts of Jewish practice. We daven three times a day, every day. During an average week, without chagim or yom tovim, we daven/listen to torah reading for approximately 375 minutes! We daven at least 22140 minutes (369 hours - that is around 8.4% of the number of hours that we are awake) per year! That's a huge part of our precious time! So what's the point? Is it for us? Is it for Hashem?
(א) מִצְוַת עֲשֵׂה לְהִתְפַּלֵּל בְּכָל יוֹם שֶׁנֶּאֱמַר (שמות כג כה) ״וַעֲבַדְתֶּם אֵת ה׳ אֱלֹהֵיכֶם״. מִפִּי הַשְּׁמוּעָה לָמְדוּ שֶׁעֲבוֹדָה זוֹ הִיא תְּפִלָּה שֶׁנֶּאֱמַר (דברים יא יג) ״וּלְעָבְדוֹ בְּכָל לְבַבְכֶם״ אָמְרוּ חֲכָמִים אֵי זוֹ הִיא עֲבוֹדָה שֶׁבַּלֵּב זוֹ תְּפִלָּה. וְאֵין מִנְיַן הַתְּפִלּוֹת מִן הַתּוֹרָה. וְאֵין מִשְׁנֶה הַתְּפִלָּה הַזֹּאת מִן הַתּוֹרָה. וְאֵין לַתְּפִלָּה זְמַן קָבוּעַ מִן הַתּוֹרָה:
(1) To pray daily is an affirmative duty, as it is said, "And ye shall serve the Lord, your God" (Exodus 23:25). The service, here referred to, according to the teaching of tradition, is Prayer, as it is said, "And to serve Him with all your heart" (Deuteronomy 11:13), on which the sages commented, "What may be described as Service of the Heart? Prayer". The number of prayers is not prescribed in the Torah. No form of prayer is prescribed in the Torah. Nor does the Torah prescribe a fixed time for Prayer. Hence, women and slaves are under an obligation to pray, this being a duty, the fulfillment of which is independent of set periods.
According to many, this pasuk is the source for the mitzvah of tefillah:
(א) ועבדתם. ...... ועבודת השם היא לעשות כל אשר צוה לאהבה אותו ולדבקה בו ולהשבע בשמו ולהתפלל אליו ולזבוח לפניו תמידין ומוספין ......
You shall serve ..... And Avodat Hashem is to all that he commands, to love him, to connect with him, to swear in his name, to pray to him, and to offer to him timidin and musafim (types of korbanot)
..............
If this pasuk is really talking about tefillah, which is in accord with many meforshim, then this seems to say that if we daven, Hashem will bless us and remove "sickness". So is the sole reason of davening for our purpose, i.e. that Hashem will bless us/provide for us? Keep this in mind for later....
Sforno and Ramban have a more intresting and far fetched approach to this pasuk:
(ה) לְהִתְפַּלַּל לוֹ, שֶׁנֶּאֱמָר: "וַעֲבַדְתֶּם, אֵת ה' אֱלֹקֵיכֶם" (שמות כג, כה) – עֲבוֹדָה זוֹ תְּפִלָּה.
(ב) שִׁמְעוֹן הַצַּדִּיק הָיָה מִשְּׁיָרֵי כְנֶסֶת הַגְּדוֹלָה. הוּא הָיָה אוֹמֵר, עַל שְׁלשָׁה דְבָרִים הָעוֹלָם עוֹמֵד, עַל הַתּוֹרָה וְעַל הָעֲבוֹדָה וְעַל גְּמִילוּת חֲסָדִים:
(2) Shimon the Righteous was from the remnants of the Great Assembly. He would say, "On three things the world stands: on the Torah, on the service and on acts of lovingkindness."
Avodat Hashem is the purpose of our lives:
(כב) אלא בריאתו של האדם, למצבו בעולם הבא היא. ועל כן ניתנה בו נשמה זאת, כי לה ראוי לעבוד, ובה יוכל האדם לקבל השכר במקומו וזמנו, שלא יהיה דבר נמאס אל נשמתו בעולם הזה, אלא אדרבא נאהב ונחמד ממנה, וזה פשוט.
(כג) והנה אחר שידענו זה, נבין מיד חומר המצוות אשר עלינו ויקר העבודה אשר בידינו, כי הנה אלה הם האמצעים המביאים אותנו אל השלמות האמיתי, אשר בלעדם לא יושג כלל.
(22) Rather, man's creation was for his state in the world to come. Therefore, this soul was placed in him, for it befits the soul to serve G-d; and through it a man will be rewarded in proper time and place. Thus this world will not be something despised to his soul, but rather beloved and cherished by it. This is evident.
(23) Behold, after knowing all this, we will immediately realize the grave obligation of the commandments upon us and the preciousness of the Divine service which lies in our hands. For these are the means which lead us to the true perfection. Without them, this state will not be attained in the least.
Many, many commentaries and philosophical scholars all agree that Tefillah is a part of Avodat Hashem (lit. the service of Hashem) , and that our purpose in life is to serve Hashem. Another essential aspect of Avodat Hashem is sacntifying each action - making each action dedicated to Hashem. Perhaps tefillah is the dedication of speech to Hashem.... So if Tefillah is part of Avodat Hashem, is it's purpose for us or for Hashem?
So if Hashem doesn't always hear our tefillot, does this impact the purpose of our tefillot?
(ו) ה' יראה ללבב הוא לא יביט רק ללבב. על צורתו הפנימית אם היא יפה בתכונותיה ונאה במדותיה זה האיש היפה אצלו הגם שחיצונית האיש שפל הקומה ומכוער המראה :
If Hashem knows my thoughts, needs, and actions, why do I need to daven? If you would say that we daven so we wont be punished for all the bad things that we do....
Let's go back to the beggining - what is the shoresh of tefillah and what does it mean?
To intervene, judge, impose, etc.
Tefilah is derived from the reflexive form of this shoresh (lehitpallel) so it literally means to judge oneself. This seems to imply that tefillah is really for us.
(YU Torah - Rabbi Weil)
So really tefillah is for ourselves. When we daven, we are forced to think about ourselves and our actions. This is called self-realization. Whether you realize it or not, davening brings out your true self and allows for one to do self-realization if they utilize the oppurtunity to daven. Rav Yosef Soleivitchik once wrote about tefillah, that the purpose of tefillah is to connect to Hashem (dvaikut) and this connection with Hashem helps us improve.