Isaiah's hearing warning in Rome
As some of Rome's Jewish leaders refuse to believe, Paul says that the Holy Spirit spoke through Isaiah and quotes the warning about hearing without understanding and seeing without perceiving.
And He replied: “Go and tell this people, ‘Be ever hearing, but never understanding; be ever seeing, but never perceiving.’ Make the hearts of this people calloused; deafen their ears and close their eyes. Otherwise they might see with their eyes, hear with their ears, understand with their hearts, and turn and be healed.”
Isaiah 6:9-10 commissions Isaiah to speak to a people who hear without understanding and see without perceiving; Acts 28:25-27 names Isaiah and quotes that warning before Paul announces that God's salvation has been sent to the Gentiles.