Isa 6:9 And he said, "Go, and say to this people: "'Keep on hearing, but do not understand; keep on seeing, but do not perceive.'
Isa 6:10 Make the heart of this people dull, and their ears heavy, and blind their eyes; lest they see with their eyes, and hear with their ears, and understand with their hearts, and turn and be healed."
Isa 6:11 Then I said, "How long, O Lord?" And he said: "Until cities lie waste without inhabitant, and houses without people, and the land is a desolate waste,
BTW-Isaiah 6:8 is frequently quoted in missions to save the lost. However, this was not Isaiah’s mission according to Isa 6:9-11. It was exactly opposite.