'Hearts' in the Bible

That their hearts might be comforted, being knit together in love, and unto all riches of the full assurance of understanding, to the acknowledgement of the mystery of God, and of the Father, and of Christ;

And let the peace of God rule in your hearts, to the which also ye are called in one body; and be ye thankful.

Let the word of Christ dwell in you richly in all wisdom; teaching and admonishing one another in psalms and hymns and spiritual songs, singing with grace in your hearts to the Lord.

Whatever you are doing, let your hearts be in your work, as a thing done for the Lord and not for men.

Whom I have sent unto you for the same purpose, that he might know your estate, and comfort your hearts;