'Hearts' in the Bible

My goal is that their hearts, having been knit together in love, may be encouraged, and that they may have all the riches that assurance brings in their understanding of the knowledge of the mystery of God, namely, Christ,

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

I sent him to you for this very purpose, that you may know how we are doing and that he may encourage your hearts.