'Heart' in the Bible

Live lives which shall prove your change of heart; and do not begin to say to yourselves, 'We have Abraham as our forefather,' for I tell you that God can raise up descendants for Abraham from these stones.

A good man from the good stored up in his heart brings out what is good; and an evil man from the evil stored up brings out what is evil; for from the overflow of his heart his mouth speaks.

"'Thou shalt love the Lord thy God,'" he replied, "'with thy whole heart, thy whole soul, thy whole strength, and thy whole mind; and thy fellow man as much as thyself.'"

For where your wealth is stored, there also will your heart be.

But if that servant should say in his heart, 'My Master is a long time in coming,' and should begin to beat the menservants and the maids, and to eat and drink, drinking even to excess;

And when he has found it, he lifts it on his shoulder, glad at heart.

He also taught them by a parable that they must always pray and never lose heart.