'Unable' in the Bible

Why do you misunderstand what I am saying? It is because [your spiritual ears are deaf and] you are unable to hear [the truth of] My word.

Jesus said to them, “If you were blind [to spiritual things], you would have no sin [and would not be blamed for your unbelief]; but since you claim to have [spiritual] sight, [you have no excuse so] your sin and guilt remain.

Therefore they could not believe, for Isaiah said again,