'Hearts' in the Bible

And he shall go before his face in the spirit and power of Elijah, to turn the hearts of the fathers to the children, and the disobedient to walk in the wisdom of the just; to make ready for the Lord a people prepared for him .

yea and a sword shall pierce through thine own soul; that thoughts out of many hearts may be revealed.

And as the people were in expectation, and all men reasoned in their hearts concerning John, whether haply he were the Christ;

But Jesus perceiving their reasonings, answered and said unto them, Why reason ye in your hearts?

And he said unto them, Ye are they that justify yourselves in the sight of men; but God knoweth your hearts: for that which is exalted among men is an abomination in the sight of God.

Settle it therefore in your hearts, not to meditate beforehand how to answer:

But take heed to yourselves, lest haply your hearts be overcharged with surfeiting, and drunkenness, and cares of this life, and that day come on you suddenly as a snare: