מדרש אויף תהילים 105:9

[2] Another interpretation: Regarding this matter, I found one person out of a thousand. This is Abraham, and how so? It was expected that until Abraham stood up, a thousand generations would pass, and then Abraham would come. Similarly, David said, "He commanded His word to a thousand generations, the covenant which He made with Abraham" (Psalm 105:8). And when God saw that there was no one among them worthy, except for all of them being wicked, He rolled them up and skipped over twenty generations, and then created Abraham. Therefore, it is said, "I have found one man out of a thousand" (Ecclesiastes 7:28), he found the greatest man among giants [Anaqim] (Joshua 14:15). Similarly, Elkanah was found as a righteous person, unique in his generation, and all his deeds are similar to Abraham's. Abraham is called a prophet, as it is said, "For he is a prophet" (Genesis 20:7), and Elkanah is also called a prophet, as it is said, "And there came a man of God unto Eli" (1 Samuel 2:27), this is Elkanah. Abraham acquired for God the heavens and the earth, as it is written, "Blessed be Abram of God Most High, Maker of heaven and earth" (Genesis 14:19). And Elkanah also acquired for God the heavens and the earth, as it is said, "And his name was Elkanah" (1 Samuel 1:1), who acquired for God the heavens and the earth. Abraham is called "one," as it is written, "Abraham was one" (Ezekiel 33:24), and Elkanah is also called "one," as it is written, "And there was a certain man" (1 Samuel 1:1).