Matthew 5 v 8
Blessed are the pure in heart: for they shall see God.
Matthew 5 v 28
But I say unto you, That whosoever looks on a woman to lust after her has committed adultery with her already in his heart.
Matthew 6 v 21
For where your treasure is, there will your heart be also.
Matthew 11 v 29
Take My yoke upon you, and learn of Me; for I am meek and lowly in heart: and you shall find rest unto your souls.