Midrash sa Deuteronomio 9:18: Devarim Rabbah, Mekhilta DeRabbi Yishmael, Ein Yaakov (Glick Edition) & Seder Olam Rabbah

“I pleaded with the Lord at that time, saying” (Deuteronomy 3:23).
“I pleaded with the Lord” – halakha: If a person of Israel is standing and praying, is it permitted for him to pray in a loud voice? So taught our Sages: If one was standing and praying, may he, perhaps, make his voice heard? Hannah already articulated this: “Hannah, she was speaking in her heart” (I Samuel 1:13). May he, perhaps, recite all three¹All three daily prayers. as one? This was already articulated in Daniel: “And three times a day he knelt on his knees, and prayed, and gave thanks before his God” (Daniel 6:11). May he, perhaps, pray at any time that he wishes? David already articulated: “Evening and morning and noon, I speak and cry aloud, and He hears my voice” (Psalms 55:18). May he, perhaps, demand [that God provide for] his needs and leave? Solomon already articulated: “To hear the cry and the prayer” (I Kings 8:28); “cry” – this is praise of the Holy One blessed be He; “and prayer” – for a person’s needs.
Abba Shaul says: This is an indicator regarding prayer – if a person focused his heart for prayer, he may be certain that his prayer is heard, as it is stated: “You will focus their heart; You will incline Your ear” (Psalms 10:17).
Rabbi Yoḥanan said: Prayer is called by ten expressions, and these are: Shava, tze’aka, ne’aka, rina, pegia, bitzur, keria, nipul, pilul, and taḥanunim. Shava and tze’aka, as it is stated: “The children of Israel sighed due to the work, and they cried out [vayizaku] [and their plea [shavatam] rose to God]” (Exodus 2:23). Ne’aka, as it is written: “God heard their groan [naakatam]” (Exodus 2:24). Rina and pegia, as it is written: “Do not pray on behalf of this people, and do not lift up a cry [rina] or a prayer on their behalf, and do not plead [tifga] with Me, [for I am not listening to you]” (Jeremiah 7:16). Bitzur and keria, as it is written: “In my distress [batzar] I called [ekra] to the Lord” (Psalms 18:7). Nipul, as it is written: “I threw myself down [va’etnapal] before the Lord” (Deuteronomy 9:18). Pilul, as it is written: “Pinḥas stood and prayed [vayfalel]” (Psalms 106:30). Taḥanunim, as it is written: “I pleaded [va’etḥanan] with the Lord.” Of all of them Moses prayed only with the expression of plea [taḥanunim].
Rabbi Yoḥanan said: From here you learn that no creature has any claim on its Creator, as Moses, the master of all the prophets, came only with an expression of plea. Rabbi Levi said: Why did Moses come only with an expression of plea [taḥanunim]?²Why did he pray to enter the Land of Israel with the expression va’etḥanan, I pleaded, and not with one of the other terms of prayer? The parable says: Be careful not to be caught in a contradiction. How so? So said the Holy One blessed be He to Moses: “I will favor [veḥanoti] whom I favor” (Exodus 33:19). [God] said to him: ‘Upon one who has [credit] with Me, “I will have mercy” (Exodus 33:19); I will act with him with the attribute of mercy. One who does not have [credit] with Me, “veḥanoti” – I will act [mercifully] with him as a free [ḥinam] gift.’ When Moses sought to enter the Land of Israel, the Holy One blessed be He said to him: “It is enough for you; [do not continue speaking to Me about this matter]” (Deuteronomy 3:26). [Moses] said before Him: ‘Master of the universe, did You not say this to me: One who does not have [credit] with Me, “veḥanoti” – I will act [mercifully] with him as a free [ḥinam] gift? Now I am not saying that anything is due to me from You, but act with me with grace [ḥinam].’ From where is this derived? From what we read regarding the matter: “I pleaded [va’etḥanan] with the Lord.”

What is, “in all of our calling to Him”? The Rabbis said: There is prayer that is answered after forty days. From whom do you derive this? From Moses, as it is written: “I fell before the Lord, as at the first, forty days…” (Deuteronomy 9:18).³³The following verse concludes: “And the Lord heeded me that time as well” (Deuteronomy 9:19). There is prayer that is answered after twenty days. From whom do you derive this? From Daniel, as it is written: “I ate no tasty bread…until the completion of three weeks of days” (Daniel 10:3), and then he said: “Lord, hear; Lord, forgive…” (Daniel 9:19). There is prayer that is answered after three days. From whom do you derive this? From Jonah, as it is written: “Jonah was in the innards of the fish [for three days and three nights]” (Jonah 2:1). And then: “Jonah prayed to the Lord his God from the innards of the fish” (Jonah 2:2). There is prayer that is answered after one day. From whom do you derive this? From Elijah, as it is written: “[It was at the time of offering up the afternoon offering] that Elijah the prophet approached, and he said…[Today it will be known that You are God in Israel]” (I Kings 18:36). There is prayer that is answered after one time period.³⁴This is one twelve-hour period, either one day or one night. From whom do you derive this? From David, as it is written: “But as for me, let my prayer come to You, Lord, at a time of favor” (Psalms 69:14). There is a prayer that even before it is expressed from his mouth, the Lord will answer, as it is stated: “It will be, before they call, I will answer” (Isaiah 65:24).

R. Eliezer says: The Holy One Blessed be He said to Moses: Moses, My children are in trouble. The sea is raging and the foe is pursuing and you stand and prolong your prayers? For R. Eliezer was wont to say: There is a time to prolong (prayer) and a time to shorten. (Numbers 12:13) "G–d, I pray You, heal her" — to shorten. (Devarim 9:18) "And I fell down before the L–rd (in prayer) as at first, forty days and forty nights" — to prolong.