'Heart' in the Bible

But as it is written, "Things which an eye didn't see, and an ear didn't hear, which didn't enter into the heart of man, these God has prepared for those who love him."

But he who stands steadfast in his heart, having no necessity, but has power over his own heart, to keep his own virgin, does well.

And thus the secrets of his heart are revealed. So he will fall down on his face and worship God, declaring that God is among you indeed.