Midras Mazmur 62:9: Pirkei DeRabbi Eliezer, Midrash Tehillim & Aggadat Bereshit

And everything is revealed before the Holy One, blessed be He. A daughter of kings, who in all her life had never gone forth to draw water, went out to draw water in that hour. And the girl, who did not know who the man was, accepted (the proposal) to be married to Isaac. Why? Because she had been destined for him from his mother's womb, as it is said, "In the balances they will go up, they are together lighter than vanity" (Ps. 62:10).

Trust Him at all times. Rabbi Chiya bar Abba of Yaffo said, "This soul, every hour that it goes up and down and seeks to leave the person, how does it stay within him? Rather, the Holy One, blessed be He, fills the entire earth with His glory, places it in the body, and it comes to leave, sees its Creator, and returns backwards." And what is the meaning of "You alone are the Lord; You made the heavens, the heaven of heavens, and all their host, the earth and all that is on it, the seas and all that is in them. You give life to all of them" (Nehemiah 9:6)? The Great Assembly explained this verse. And from where do we know that the glory of the Holy One, blessed be He, fills the world? As it is said, "Do I not fill the heavens and the earth? says the Lord" (Jeremiah 23:24). Rabbi Chiya said in the name of Rabbi Meir's students, "This is how they used to sing (Psalms 150:6), 'Let every soul praise God.' What does 'let every soul praise God' mean? Every hour that it goes up and down in the body, we must say Hallelujah. Praise God for the wonders that He does with us every hour without us realizing it. Trust Him at all times. Pour out your heart before Him. God is our refuge. Selah."

[2] Another interpretation: When it was time to present the meal offering (1 Kings 18:36) David said, "My prayer, O Lord, is at an opportune time" (Psalm 69:14). God has appointed a time for everything except prayer. When should one pray in order to be answered? As it says, "For every desire there is a time and a judgment" (Ecclesiastes 8:6). If a person knew when to pray and be answered, he would only pray on that day. Therefore, God said, "I will not let you know when you will be answered, so that you will pray at all times" as it says, "Trust in Him at all times" (Psalm 62:9). Even the forefathers of the world were sometimes answered and sometimes not. Moses, the great leader of the world, prayed and was answered, as it says, "And the Lord did as Moses asked" (Exodus 8:17). And so it says, "I have forgiven you as you asked" (Numbers 14:20). But sometimes, even when he prayed, he was not answered, as it says, "But the Lord was angry with me because of you" (Deuteronomy 3:26). David was answered at all times, as it says, "I sought the Lord and He answered me" (Psalm 34:5), and also, "And He answered him from heaven with fire" (1 Chronicles 21:26). When was he not answered? When the child was sick and he fasted, lay on the ground, and begged for mercy, but in the end the child died. When is the opportune time for everyone? As it says, "At an opportune time I answered you" (Isaiah 49:8). David said to God, "Master of the universe, every hour that I pray, make it an opportune time for me to be answered" as it says, "My prayer, O Lord, is at an opportune time" (Psalm 69:14). When is the opportune time? It is the afternoon prayer, as it says, "And it came to pass at the time of the evening offering" (1 Kings 18:36).