Midrash sa Mga Awit 142:3: Mekhilta DeRabbi Yishmael, Bereshit Rabbah & Midrash Tehillim

Isaac — (Ibid. 24:63) "And Isaac went out lasuach in the field," "sichah" being prayer, as in (Psalms 55:18) "Evening, morning, and noon asichah and moan, and He has heard my voice," and (Ibid. 14:2-3) "With my voice I cry out to the L–rd. I pour out before Him sichi. I tell my trouble before Him, etc.", and (Ibid. 102:1) "A prayer of the afflicted one when he faints, and before the L–rd pours forth sicho."

“He encountered the place and spent the night there because the sun had set; he took from the stones of the place, which he placed beneath his head, and lay down in that place” (Genesis 28:11).
“He encountered [vayifga] the place” – Rav Huna said in the name of Rabbi Ami: Why do they change the name of the Holy One blessed be He and call Him the Omnipresent [hamakom]? It is because He is the place [mekomo] of the world, and His world is not His place. From what is written: “Behold, there is a place [makom] with Me” (Exodus 33:21) – the Holy One blessed be He is the place of the world, and His world is not His place.¹¹God is not contained in the world, he does not "live" there. He is the "place" of the world. The world exists because of Him.
Rabbi Yitzḥak said: It is written: “An abode of the God of eternity” (Deuteronomy 33:27). We do not know whether the Holy One blessed be He is the abode of the world, or whether the world is His abode. From what is written: “You are an abode for us” (Psalms 90:1) – that is, the Holy One blessed be He is the abode of the world, but His world is not His abode.
Rabbi Abba bar Yudan said: This is analogous to a warrior who was riding on a horse, and his garments were flowing to both sides. The horse is secondary to the rider, but the rider is not secondary to the horse, as it is stated: “You will ride on Your horses” (Habakkuk 3:8).
Another matter, what is vayifga? He prayed. “In the place” – he prayed in the Temple. Rabbi Yehoshua ben Levi said: The early patriarchs instituted three prayers: Abraham instituted the morning prayer, as it is stated: “Abraham arose early in the morning to go to the place where he stood…” (Genesis 19:27), and standing is nothing other than prayer, as it is stated: “Pinḥas stood and prayed” (Psalms 106:30). Isaac instituted the afternoon prayer, as it is stated: “Isaac went out walking [lasuaḥ] in the field” (Genesis 24:63), and siḥa is nothing other than prayer, as it is stated: “I will pour out [eshpoḥ] my woe before Him” (Psalms 142:3). Jacob instituted the evening prayer, as it is stated: “He encountered [vayifga] the place,” and pegia is nothing other than prayer, as it is stated: “You, do not raise a cry [or a prayer] on their behalf, and do not plead with [tifga] Me” (Jeremiah 7:16). Likewise it says: “If they are prophets, and if the word of the Lord is with them, please, let them plead [yifge’u] with the Lord of hosts” (Jeremiah 27:18). Rabbi Shmuel bar Naḥman said: It is corresponding to the three times that the day changes. In the evening, a person must say: ‘May it be Your will, Lord my God, to take me out from darkness to light.’ In the morning, he must say: ‘I give thanks before You, Lord my God, that You have taken me from darkness to light.’ In the afternoon, a person must say: ‘May it be Your will, Lord my God, that just as you accorded me the privilege of seeing the sun in its rising, so You will accord me the privilege to see it in its setting.’
Another matter, “he encountered the place” – the Rabbis say: It is corresponding to the daily offerings.¹²The midrash is giving an alternative source for the three daily prayers. The morning prayer, corresponding to the daily morning offering; the afternoon prayer, corresponding to the daily afternoon offering; the evening prayer is not obligatory. Rabbi Tanḥuma said: Even the evening prayer is obligatory – corresponding to the limbs and fats that were consumed in the fire on the altar.¹³The limbs and fats were also consumed in the fire at night.

Another interpretation of prayer for the poor who is suffering. Rabbi Pinchas said in the name of Rabbi Reuben, "I cannot understand David's state of mind. Sometimes he calls himself poor, and sometimes he calls himself David. But when he saw righteous people like Asa, Hezekiah, and Josiah standing before him, he called himself David. And when he saw wicked people like Ahaz, Ammon, and Manasseh standing before him, he called himself poor." Rabbi Samuel said in the name of Rabbi Nathan, "In reference to Manasseh, they said a prayer for the poor who is suffering because he was poor in good deeds." Rabbi Alexandri said in reference to the prayer, "They said, 'When the one who comes to beg approaches her, let him kneel down like it says, 'And it shall be that the one who kneels down.'" "And only prayer is called kneeling down, as it says, 'My soul is bowed down upon me.'" Rabbi Meir and Rabbi Yossi disagreed on when a person should make their requests known before praying. One said a person should make their requests first, and then pray, as it says, "Prayer for the poor who is suffering." "When will this be? When he kneels down." The other said a person should pray first, and then make their requests known, as it says, "I will pour out my thoughts before Him, and I will relate my troubles to Him." And there is no conversation except prayer, as it says, "Isaac went out to converse in the field towards evening." Rabbi Zeira said in the name of Rav Huna, "Everyone agrees that he makes his requests known in the presence of one who listens to prayer, as it says, 'Hear my prayer.'"...