Midras Yesaya 50:10: Ein Yaakov (Glick Edition), Midrash Tehillim & Bereshit Rabbah

Rabin b. R. Ada in the name of R. Isaac said: "Whoever frequents the synagogue [daily] and misses one day, the Holy One, praised be He! inquires about him; for it is written (Is. 50, 10.) Who is among you, that feareth the Lord, that hearkeneth to the voice of His servant? Though he has walked in darkness and had no light, let him trust in the name of the Lord; i.e., if he went to perform a meritorious deed [and was therefore absent from synagogue] there will be light unto him; but if his absence is due to personal business, then there will be no light unto him for he should have placed his trust in God." R. Jochanan said: When the Holy One, praised be He! enters the synagogue and does not find ten [men] present, His anger is immediately stirred, as it is said (Is. 50, 2.) Why did I come and no man was there, did I call with none to answer."

Psalm of David: In you, Lord, I have taken refuge. As it is said in the scripture (Isaiah 50:10), "Who among you fears the Lord and obeys the word of his servant? Let the one who walks in the dark, who has no light, trust in the name of the Lord and rely on their God." When Israel enters synagogues and says before the Lord, "Redeem us," He tells them that there are righteous and God-fearing people among them. They reply that in the past, during the days of Moses, Aaron, Saul, David, and Solomon, there were righteous people, but now they have been taken away from them because of their sins. As it says in Isaiah 57:1, "The righteous perish, and no one takes it to heart; the devout are taken away, and no one understands that the righteous are taken away to be spared from evil." And it says in Psalm 12:2, "Everyone lies to their neighbor; they flatter with their lips but harbor deception in their hearts." We have no one to rely on, for everything we do leads us into darkness, as it is said in Isaiah 50:10, "Whoever walks in the dark does not know where they are going." The Lord tells them to trust in His name, for He is their support. As it says in Isaiah 50:10, "Let them trust in the name of the Lord and rely on their God." And He will save anyone who trusts in His name, as He saved Hananiah, Mishael, and Azariah, who trusted in Him, as it says in Daniel 3:28, "Blessed be the God of Shadrach, Meshach and Abednego, who has sent his angel and rescued his servants!" And Daniel trusted in Him, and He saved him from the pit, as it says in Daniel 6:24, "And the king gave the order, and they brought Daniel and threw him into the lions' den. The king said to Daniel, 'May your God, whom you serve continually, rescue you!'" David said, "Since this is the confidence that anyone who trusts in You will be saved, I also trust in You."

“He said: Lord, God of my master Abraham, please arrange it for me today, and perform kindness with my master Abraham” (Genesis 24:12).
“He said: Lord, God of my master Abraham, please arrange it for me today…” “Who among you fears the Lord, who heeds the voice of His servant…” (Isaiah 50:10). “Who among you fears the Lord” – this is Abraham;¹See Genesis 22:12. “who heeds the voice of His servant…” – [this means] that the Holy One blessed be He heeded the voice of his [Abraham’s] servant. “Who walked in darkness” (Isaiah 50:10) – as he came forth from Mesopotamia and its environs, but he did not know where he was to go, like a person who is situated in the dark. “And there was no light for him” (Isaiah 50:10) – and who provided illumination for him? The Holy One blessed be He provided illumination for him every place that he would go. “Let him trust in the name of the Lord and rely on his God” (Isaiah 50:10) – “[You called his name Abraham,] and You found his heart faithful before You” (Nehemiah 9:7–8).
Another interpretation, “Who among you fears the Lord” – this is Eliezer; “who heeds the voice of His servant…” – [he heeded] the voice of Abraham who was the servant of the Holy One blessed be He, as it is stated: “For the sake of My servant, Abraham” (Genesis 26:24). “Who walked in darkness” – when he went to bring Rebecca. “And there was no light for him” – and who provided illumination for him? The Holy One blessed be He provided illumination for him, with shooting stars and lightning. “Let him trust in the name of the Lord and rely on his God” – “He said: Lord, God of my master Abraham, please arrange it for me today.”