“If you forgive the sins of any, they are forgiven them; if you withhold forgiveness from any, it is withheld.” -Jesus to the Disciples, John 20:23, ESV
Is Adultery the Unpardonable Sin?
Short answer: No. Adultery is pardonable.
But an awful sin has happened that needs pardoning.*
What does obtaining a pardon mean?
Pardon in the legal and political sense requires someone who has already been convicted of a crime. They are seeking a pardon. I am thinking especially about the sense of how a president can pardon a criminal and clear him of his crimes. The pardon is about wiping out the sentence already handed down with the conviction of the criminal as I understand it.
When it comes to forgiving adultery, Christians too often skip over the conviction part.
Has the adulterous spouse owned that they deserve their marriage to end by committing adultery (e.g. Deut. 22:22, Jer 3:8, Mt 5:32, etc)? Do they agree that they have done a grievous thing wounding many and defying God’s commands? Have they embraced that they do not deserve mercy? Are they in a humble place to receive forgiveness?
Or do they just want a quick pardon so that they can keep on sinning against God and their families without worrying about the consequences of that sin?
One does not pardon someone who is already free of ever being convicted. They have to be liable for wrongdoing to need a pardon. In other words, you did something very bad if you need a pardon.
Yes, adultery is a pardonable sin. However, the sinner must recognize she did something that needs a pardon and then humbly seek it. If adulterous spouses think they do not need a pardon, then adultery is for them an unpardonable sin as they lack both the insight and humility necessary to obtain it.
***Forgiveness is important for the faithful spouse regardless of the adulterous spouse’s state of mind. The faithful spouse needs to let go of the pain handing it over to God so that what was done no longer controls or continues to cause suffering for him or her. We do not need to punish our adulterous spouses. God sees it all, and He is both wise and just. And this process of forgiveness will take time for such deep wounds. Pardon as I use it here is more about reconciliation in marriage. I do not think pardons ought to be granted in that sense without clear conviction and evidence of humility in the adulterous spouse. It is not wise or safe to return to a marriage where the adulterous spouse remains arrogantly tied to his or her adulterous ways. Doing such knowingly keeps the door open to further sin and causes damage to both partners emotionally and spiritually as I see it.