 He probably read Jeremiah 25, 11, Jeremiah 25, 12, Jeremiah 29, 10, because all of those verses talk about the 70 years. And he said, I know what God's purpose is. God's purpose is 70 years. And consistent with God's revelation, I can now pray for God to send my people back because it's consistent with the time frame He's established in His own Word. And so the first thing you learn about prayer is that prayer is to be lined up with the revelation of God.