'Dull' in the Bible

For this people's heart is waxed gross, and their ears are dull of hearing, and their eyes they have closed; lest at any time they should see with their eyes, and hear with their ears, and should understand with their heart, and should be converted, and I should heal them.

For the heart of this people is waxed gross, and their ears are dull of hearing, and their eyes have they closed; lest they should see with their eyes, and hear with their ears, and understand with their heart, and should be converted, and I should heal them.

Of whom we have many things to say, and hard to be uttered, seeing ye are dull of hearing.