“He who covers his sins will not prosper,
but he who confesses and forsakes them shall obtain mercy.”
“If we confess our sins, he is faithful and just
to forgive us our sins,
and to cleanse us from all unrighteousness.”
“If your brother sins against you, rebuke him;
and if he repents, forgive him.”
Jesus, in Matthew 18:15
To have a tender heart and to be willing and ready to forgive is the way Jesus taught us to live, but to be willing to forgive it is different from actually forgiving. No one should be hard-hearted toward those who have done wrong because God was not hard-hearted toward any of us, but true forgiveness only exists as a response to true repentance. True, healing forgiveness is never extended or experienced until the ingredient of repentance is added to the transgression.
To forgive a killer who does not sincerely regret his crime is no more than an invitation for him to kill again. The same can be said of thieves, adulterers, and so forth. The betrayed wife who “forgives” her adulterous husband without him confessing and forsaking his sinful ways cannot be said to be showing him true forgiveness him at all. Rather, through ignorance of how to forgive in a godly manner, she is rewarding him with undeserved pardon and, therefore, encouraging him, if not granting him a license, to continue with his infidelity. She is not showing him either the love or the mercy of God because God isn’t like that. He will not forgive those who do not repent.
To offer forgiveness before the guilty party repents may be "the Christian thing to do", but it is not the godly thing to do. God, who is so full of mercy that His throne is called “the mercy seat”, has never forgiven any sinner who refused His call to repentance. Christians, on the other hand, regularly demand that we forgive unconditionally, which is utter foolishness in the guise of mercy.