Halachic Corner: How Much Should One Pray for a Specific Matter?
Persistence in prayer: Is it appropriate to repeatedly petition Hashem for the same request?

Question: Is it proper for a person to repeatedly plead before Hashem for the same matter every day? Wouldn't it be more appropriate to pray for something a few times, and after seeing no response, cease praying for this matter?
Answer: In the Talmud, Tractate Berachot (32), we learn: "Rabbi Chanina said: Whoever extends his prayer, his prayer does not return empty. How do we know this? From Moses, as it says, 'And I prayed to Hashem for forty days and forty nights,' and afterward it says, 'And Hashem listened to me also at that time.'" From here, we learn that one who extends (or increases) his prayers, his prayer is heard.
The Talmud then raises a difficulty, for "Rabbi Yochanan said: Whoever extends his prayer and contemplates it, will ultimately suffer heartache." This suggests that it's better for a person not to extend and increase too much in requests, because if one increases requests and extends prayer, one will ultimately suffer heartache. As it says in the Book of Proverbs, "Hope deferred makes the heart sick." The Talmud resolves this: "Here [it refers to] one who extends and contemplates it, and here [it refers to] one who extends but does not contemplate it."
In other words, what they said about extending prayer, and that whoever extends his prayer will ultimately have his prayer heard, applies specifically when "he does not contemplate it" – meaning, he doesn't constantly think that because he extends his prayer, his prayer should be accepted. And what Rabbi Chiya bar Abba said, that whoever extends prayer will ultimately suffer heartache, applies specifically when "he contemplates it" – when he thinks his request will be fulfilled because he extends his prayer. Since he expects his request to be fulfilled through his prayer – his request is not fulfilled, and he suffers heartache, as he continuously awaits the fulfillment of his desire, but his desire doesn't come.
Similarly, in the Talmud Berachot (51), they said: "Whoever extends his prayer will ultimately suffer heartache, and Rabbi Yitzchak further said: Whoever extends his prayer causes his sins to be mentioned before Hashem." The Talmud explains that all these statements apply when one "contemplates his prayer," and Rashi explains: "He says in his heart that his request will be fulfilled because he prayed with intention."
From here, it is proper for a person to increase prayer greatly. Even if after a thousand prayers he is not answered, it's possible that with one additional prayer his request will be fulfilled. However, he should not become proud in his heart and think that because of his persistence in prayer with intention his wish will be fulfilled; rather, he should sit and await Hashem's abundant mercy, perhaps He will have compassion. As the Meiri wrote: "One should not praise himself for having excelled in intention, thinking that he deserves his prayer to be accepted," but rather, one should behave with humility and hope for Hashem's mercy, that He will deal with him with the attribute of kindness, hear his prayer, and grant his request.