Like a person who is injured physically and develops a scab at that place of hurt, so the same thing can happen to your heart.
The enemy can convince you that hardening your heart is necessary to protect you from further hurt.
But the Lord gave me this Word on this subject:
"Unless you allow the Lord to heal your heart, you will never grow past the place of your wounding."
In the following article are some truths about Jesus that can help soften the hard heart – if the person will believe.
I also included my prayer for a person suffering from a hard heart in the article.