Malachi 2:14

2:14 Yet you ask, “Why?” The Lord is testifying against you on behalf of the wife you married when you were young, to whom you have become unfaithful even though she is your companion and wife by law.

Proverbs 4:23

4:23 Guard your heart with all vigilance,

for from it are the sources of life.

Proverbs 6:25

6:25 Do not lust in your heart for her beauty,

and do not let her captivate you with her alluring eyes;

Proverbs 7:25

7:25 Do not let your heart turn aside to her ways –

do not wander into her pathways;

Matthew 5:28-29

5:28 But I say to you that whoever looks at a woman to desire her has already committed adultery with her in his heart. 5:29 If your right eye causes you to sin, tear it out and throw it away! It is better to lose one of your members than to have your whole body thrown into hell.

Matthew 15:19

15:19 For out of the heart come evil ideas, murder, adultery, sexual immorality, theft, false testimony, slander.

James 1:14-15

1:14 But each one is tempted when he is lured and enticed by his own desires. 1:15 Then when desire conceives, it gives birth to sin, and when sin is full grown, it gives birth to death.