ACTS 28:27
"For the hearts of these people are hardened , and their ears can not hear, and they have closed their eyes- so their eyes can not see, and their ears can not hear, and their hearts can not understand, so that they could turn to me for healing."
How many people do you know that have heard the Word of God and yet they do not understand it? How many people can see what God has done and still can not comprehend it? That is why in this scripture Paul is told to say to the Jews, that their hearts have hardened, their eyes can not see and their ears can not hear. If they did open their heart and see with their eyes or hear with their ears, they would have turned to Jesus Christ so that he could heal them. Truly hearing the Word they do not hear nor understand, and seeing they do not see nor do they perceive!
Nothing has changed since Paul was told to go and tell the Jews this message. They believe in God the Father but they have never opened their heart to Jesus nor have they truly heard the Word of God, nor seen His Light, the Lord Jesus Christ. They have hardened their heart and become a stiff necked and rebellious people. That is why God sent His Salvation unto the gentiles. The gentiles have heard and seen and opened their heart to the Lord Jesus Christ!
The heart or the soul with its understanding can grow dull, hardened, calloused and make a person stupid. Ones ears can become heavy and hard of hearing. You can shut your eyes tight and never perceive or become acquainted and knowledgeable about Jesus. They real pity is that under these conditions you will never see with your eyes or hear with your ears or understand with you heart and soul. Thus you will never turn to the only one that can heal you of your condition. Jesus Christ wants to heal you. Do not be HARD HEARTED!