'Dull' in the Bible

“His eyes are dull from wine,And his teeth white from milk.

If the axe is dull and he does not sharpen its edge, then he must exert more strength. Wisdom has the advantage of giving success.

“Render the hearts of this people insensitive,Their ears dull,And their eyes dim,Otherwise they might see with their eyes,Hear with their ears,Understand with their hearts,And return and be healed.”

Behold, the Lord’s hand is not so shortThat it cannot save;Nor is His ear so dullThat it cannot hear.