ת"ר מתריעין על פרקמטיא ואפי' בשבת. א"ר יוחנן כגון כלי פשתן בבבל ויין ושמן בארץ ישראל אמר רב יוסף והוא דזל וקם עשרה בשיתא
Apropos price fluctuations, the Gemara cites a baraita. The Sages taught: A community sounds the alarm and gathers in public prayer for merchandise [perakmatya] whose price has dropped. And even on Shabbat it is permitted to cry and plead, even though one may not pray for his personal needs on Shabbat, as this hardship affects the entire public. Rabbi Yoḥanan said: The baraita is referring specifically to merchandise that serves as the basis of the local economy, such as linen garments in Babylonia, and wine and oil in Eretz Yisrael. Rav Yosef said: And that halakha, that public prayer is recited even on Shabbat, applies only when the merchandise was reduced in price and stood at such prices that goods that had been worth ten are currently selling for six.
מפני מה זה ירד וזה לא ירד זה ניצל וזה לא ניצל זה התפלל ונענה וזה התפלל ולא נענה מפני מה זה נענה וזה לא נענה זה התפלל תפלה שלימה נענה וזה לא התפלל תפלה שלימה לא נענה ר' אלעזר אמר כאן קודם גזר דין כאן לאחר גזר דין רבי יצחק אמר יפה צעקה לאדם בין קודם גזר דין בין לאחר גזר דין
For what reason did this one recover and come down from his bed, while that one did not recover and come down from his bed; and why was this one saved from death, while that one was not saved? The difference between them is that this one prayed and was answered, while that one prayed, but was not answered. And for what reason was this one answered and that one not answered? This one prayed a prayer with his whole heart and consequently was answered, while that one did not pray a prayer with his whole heart and therefore was not answered. Rabbi Elazar said: Not so; rather, here he prayed before his heavenly sentence was issued, and so he was answered, whereas there the other one prayed after his heavenly sentence was issued, and therefore he was not answered. Rabbi Yitzḥak disagreed and said: Crying out to God is effective for a person, both before his sentence has been issued and also after his sentence has been issued, as even after his sentence has been issued, it can still be rescinded if he repents.
-Esther Wachsman, 2000
When we are faced with some very serious problems, it is customary to ask others to join together in our prayers. What is that all about? It seems as if we hope to move G-d through force: “G-d, if you don’t respond to my prayers, then I will recruit through the e-mail thousands of others to pray.” Do we think these strategies really work? What are we actually doing here? If G-d is all knowing then why am I telling Him my problems? He already knows them. If G-d is good then why am I asking for Him to change my situation?
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If you are under the impression that praying is communicating to G-d information that He does not already know, then the whole prayer experience becomes ridiculous. G-d knows that your business is falling apart. G-d knows that you desperately want your soul-mate. G-d knows exactly what is going on in your life. L’hispallel is not about G-d hearing your prayer, although He surely does. It is about you hearing your prayers. You need to say these things to G-d because you need to hear yourself saying them.
L’hispallel means to do something to yourself. ... It is not G-d whom we are trying to change. It is ourselves and our relationship to G-d we are trying to change through prayer. If we change ourselves, we change our whole situation.
-Rabbi David Aaron, 2015
-Abraham Joshua Heschel