'Hearts' in the Bible

is it not plain that in your hearts you have little faith, seeing that you have become judges full of wrong thoughts?

But if in your hearts you have bitter feelings of envy and rivalry, do not speak boastfully and falsely, in defiance of the truth.

Or do you suppose that it is to no purpose that the Scripture says, "The Spirit which He has caused to dwell in our hearts yearns jealously over us"?

Draw near to God, and He will draw near to you. Cleanse your hands, you sinners, and make your hearts pure, you who are half-hearted towards God.