ונראה כי ה' ניסה אותם להדריכם לשאת עיניהם ולהתפלל לפני ה' כי זה עיקר גדול באמונה ובהשלמת הנפש.
It appears that G'd's purpose in subjecting the people to this test was to train them to raise their eyes heavenwards, to pray and to implore G'd in times of need because this is an important principle in matters of faith and attempts to perfect one's personality.
(א) ה' אלקים צבאות שמעה תפלתי האזינה אלקי יעקב סלה (תהלים פד). פסוק זה אמרו דוד ע"ה והיה מתחנן להקב"ה שישמע תפלתו לפי שעם התפלה יתקרב אדם לבוראו
... This Pasuk states that Dovid was pleading to Hashem to listen to his prayer as with tefillah man draw close to Hashem
Why do we ask Hashem for all of these things and then at the very end ask him not to return us empty handed? Isn't that insulting?
וְהִ֖יא מָ֣רַת נָ֑פֶשׁ וַתִּתְפַּלֵּ֥ל עַל־יְהֹוָ֖ה וּבָכֹ֥ה תִבְכֶּֽה׃
In her wretchedness, she prayed to the LORD, weeping all the while.
And she made this vow: “O LORD of Hosts, if You will look upon the suffering of Your maidservant and will remember me and not forget Your maidservant, and if You will grant Your maidservant a male child, I will dedicate him to the LORD for all the days of his life; and no razor shall ever touch his head.”
וּמְנָא לַן דְּבִתְפִלָּה דְּתַנְיָא לְאַהֲבָה אֶת ה׳ אֱלֹקֵיכֶם וּלְעׇבְדוֹ בְּכׇל לְבַבְכֶם אֵיזוֹ הִיא עֲבוֹדָה שֶׁהִיא בַּלֵּב הֱוֵי אוֹמֵר זוֹ תְּפִלָּה
The Gemara asks: And from where do we derive that rain must be mentioned specifically in the Amida prayer? The Gemara answers: As it was taught in a baraita with regard to the verse: “To love the Lord your God and to serve Him with all your heart” (Deuteronomy 11:13). Which is the service of God that is performed in the heart? You must say that this is referring to prayer. .
It was stated: Rabbi Yosei, son of Rabbi Ḥanina, said: The practice of praying three times daily is ancient, albeit not in its present form; prayers were instituted by the Patriarchs. However, Rabbi Yehoshua ben Levi said that the prayers were instituted based on the daily offerings sacrificed in the Holy Temple, and the prayers parallel the offerings, in terms of both time and characteristics.
רְצֵה ה אֱלֹקֵֽינוּ בְּעַמְּ֒ךָ יִשְׂרָאֵל וּבִתְפִלָּתָם וְהָשֵׁב אֶת הָעֲבוֹדָה לִדְבִיר בֵּיתֶֽךָ וְאִשֵּׁי יִשְׂרָאֵל וּתְפִלָּתָם בְּאַהֲבָה תְקַבֵּל בְּרָצוֹן וּתְהִי לְרָצוֹן תָּמִיד עֲבוֹדַת יִשְׂרָאֵל עַמֶּֽךָ:
א"ר יצחק מפני מה היו אבותינו עקורים מפני שהקב"ה מתאוה לתפלתן של צדיקים
Rabbi Yitzḥak said: For what reason were our forefathers initially infertile? Because the Holy One, Blessed be He, desires the prayers of the righteous, and He therefore wanted them to pray for children.
התפלה היא במקום הקרבן ולכן צריך ליזהר שתהא דוגמת הקרבן בכוונה ולא יערב בה מחשבה אחרת כמו מחשבה שפוסלת בקדשים...
Prayer is in place of sacrifices (korbanot), and therefore one must be careful that it resemble the sacrifices with respect to intention, and not let other thoughts mix in, similar to unrelated thoughts which would nullify sacrifices...
The reason which leads men to doubt the efficacy of prayer is the same as that which leads them to deny God’s knowledge. Their argument is as follows: Either God has determined that a given person shall receive a given benefit, or He has not so determined. If He has determined, there is no need of prayer; and if He has not determined, how can prayer avail to change God’s will that He should now determine to benefit the person, when He had not so determined before? For God does not change from a state of willing to a state of not willing, or vice versa. For this reason they say that right conduct is of no avail for receiving a good from God. And similarly they say that prayer does not avail to enable one to receive a benefit, or to be saved from an evil which has been decreed against him.
Rav Samson Raphael Hirsch, Horeb Part IV
Hitpallel, from which “Tefillah” is derived, originally meant to deliver an opinion about oneself, to judge oneself or an inner attempt at so doing such as the hitpael (reflexive) form of the Hebrew verb frequently denotes … Thus it denotes to step out of active life in order to attempt to gain a true judgment about oneself … about one’s relationship to God and the world, and the world to oneself …
In English we call Tefillah “prayer,” but this word only incompletely expresses the concept “to pray,” i.e., to ask for something is only a minor section of Tefillah.