Matthew 5:28

but I say unto you, That every one who looketh upon a woman to lust after her, hath already committed adultery with her in his heart.

Matthew 12:35

A good man out of the good treasure of his heart bringeth forth good things: and a wicked man out of the evil treasure of his heart bringeth forth evil things.

Matthew 15:19

for out of the heart proceed wicked reasonings, murders, adulteries, whoredoms, thefts, false testimonies, blasphemies:

Treasury of Scripture Knowledge

Summary

And let none of you imagine evil in your hearts against his neighbour; and love no false oath: for all these are things that I hate, saith the LORD.

Bible References

Let

Matthew 5:28
but I say unto you, That every one who looketh upon a woman to lust after her, hath already committed adultery with her in his heart.
Matthew 12:35
A good man out of the good treasure of his heart bringeth forth good things: and a wicked man out of the evil treasure of his heart bringeth forth evil things.
Matthew 15:19
for out of the heart proceed wicked reasonings, murders, adulteries, whoredoms, thefts, false testimonies, blasphemies: