'Heart' in the Bible

"He has blinded their eyes and he hardened their heart, lest they should see with their eyes, and perceive with their heart, and would turn, and I would heal them."

During supper, the devil having already put into the heart of Judas Iscariot, Simon's son, to betray him,

"Don't let your heart be troubled. Believe in God. Believe also in me.

Peace I leave with you. My peace I give to you; not as the world gives, give I to you. Don't let your heart be troubled, neither let it be fearful.

But because I have told you these things, sorrow has filled your heart.

Therefore you now have sorrow, but I will see you again, and your heart will rejoice, and no one will take your joy away from you.