Should everyone receive capital punishment as a murderer because we have been angry at someone (Matt. 5:21-22)? Jesus’ point about anger and lust (Matt. 5:21-32) is that God is also concerned about the sin on the inside. Some of the religious leaders focused on the external actions and believed it was acceptable to lust and hate on the inside. Jesus corrected that thinking. Jesus condemned lust on the inside when He said,

. . . everyone who looks on a woman to lust for her has committed adultery with her already in his heart. (NASB) Matthew 5:28

That was the internal act of sin. To follow through with our internal sinful desires is the second stage in our sin and causes other things to happen to us.

And it was said, ‘WHOEVER SENDS HIS WIFE AWAY, LET HIM GIVE HER A CERTIFICATE OF DIVORCE’; but I say to you that everyone who divorces his wife, except for the cause of unchastity, makes her commit adultery; and whoever marries a divorced woman commits adultery. (NASB) Matthew 5:31-32

Not everyone follows through with their lust or even a stated desire. If they do so and then divorce, Jesus says they do not have a biblical divorce – they are not free to remarry unless the conditions are correct. There is a consequence to acting on our desire. Jesus did not say “everyone who divorces his wife, except for the cause of LUST . . .” He specifies a physical act. There is a difference between an internal sinful urge and following through with an outward act. God will judge us for the internal act AND the outward act, but the outward act has much more serious consequences.

Conclusion:

The outward actions are a response to the inward sinful attitudes and desires.

But the things that proceed out of the mouth come from the heart, and those defile the man. For out of the heart come evil thoughts, murders, adulteries, fornications, thefts, false witness, slanders. (NASB) Matt. 15:18-19

But we do not have to yield to sin and commit the external act.

Let no one say when he is tempted, “I am being tempted by God”; for God cannot be tempted by evil, and He Himself does not tempt anyone. But each one is tempted when he is carried away and enticed by his own lust. Then when lust has conceived, it gives birth to sin; and when sin is accomplished, it brings forth death. (NASB) James 1:13-15

Divorce involves a physical act, a piece of paper called a certificate – an external act and an internal act of sin. Lust is only an internal sin. Jesus condemned both! But only the external act can prevent remarriage, according to Jesus.

Suggested Links:

Biblical Divorce and Remarriage
Is it a sin to divorce if you profess to be a Christian?
If you are divorced and remarry, are you living in adultery?
What does God say about a person marrying someone who has been divorced?
A Biblical Divorce