Conditions for Forgiveness

First, a sin must have occurred. In very general terms, a sin is when we intentionally cause an avoidable injury to another person or we violate a law given to us by God.

A sin also occurs when we engage in risky actions where injury is a foreseeable consequence. (Matt 5:21-42)

Some injuries are unavoidable and those injuries are not "sin". Regrettable, but not sin. Physics cannot be negotiated. Getting hit by a boulder is an act of God while an accident caused by driving too fast or pulling into traffic without looking is avoidable.

Forgiveness is starts when we perform a moral inventory where we look at our past and see where pain occurred. Then we evaluate our part in it causing, perpetuating or enabling that pain.

Contrite

The person who seeks forgiveness must be grieved that they cause pain to another, not because Karma bit them in the backside. Also not because they got caught. Nor because it is a "moot point", that is the sinner lost the power to cause or benefit from future sin.

Change your life

The person seeking forgiveness must be firmly committed to changing their life. Not "...want to..." but intending to make those changes. Compare "I want a Rolex watch" with "I intend to knock that guy over there on the head and steal his Rolex." "Want" is passive. "Intend" is active.

In many cases the best change involves avoiding the conditions that led them to sin. If a person has a problem with drinking then they need to stop buying bottles of whisky or stop driving down the street where their favorite bar is.

They have to stop dancing on the slippery-slope. In old-time, morality speak, they need to "avoid the near occasion of sin".

Confess their sins

God does not need to hear a laundry list of our sins. He already knows what we did. We need to say them out-loud to heal. We need to know somebody heard us and we need to hear somebody say "Know that God and this community forgives you" before we can move on.

Ideally, we confess to the person who we injured but that is not always possible because we cannot know every person we damaged or put at-risk when we sinned.

Consider somebody who drives while stupid-drunk. It is impossible to know every person whose life the drunk-driver put in danger. Confessing in front of a congregation or a representative of the Humanity will have to suffice. It might be an older brother in a deer-blind. It might be a grizzled veteran at the V.F.W. It should be somebody who will call B.S. if you are letting yourself off too easily.

Also, sometimes it is dangerous to confess to the person you injured: the Mafia Don you ripped off or the company you stole from. Confessing to a church elder, the congregation or a trusted family member will have to suffice. 

As a card-carrying Catholic I have to note that this is a generalized version of what the Catholic church teaches. I made the changes to be in alignment with a larger audience. 

I chose to not debate that it is only necessary for us to confess to God because I am focusing on the damage guilt causes to the person carrying it. Most people seem to need verification from a fellow human before they can let those feelings go.

Atone

Make amends to a degree that is approximate to the damage you caused. Repair the fence you ran over. Tell the person you injured that you are sorry. 

If the person you sinned against is not available to make-things-right, then get as close as you can. 

Many people who repeatedly sabotage their relationships do so because they keep tripping on deeply buried, unresolved guilt-issues. Perhaps over a parent who is no longer alive. Maybe an ex-girlfriend who now lives out-of-state or refuses to speak with them.

Find somebody else's parent who is going through similar struggles and do what you can to ease their pain or broker reconciliation between parent-and-child. Find a young woman who is in a similar predicament to your ex-GF and do what you can to help her.

Let me reiterate that God does not need for us to atone and do penance. God can raise loaves of bread out of stones and armies out of nothing. God does not need to have us atone. WE need to atone so we can feel Forgiven. It is that "Economy of Forgiveness" thing. We equate value with price. We are much less likely to feel Forgiven when we don't pay a reasonable price.

Bonus

A.A.'s 12 Steps

1. We admitted we were powerless over alcohol — that our lives had become unmanageable.

2. Came to believe that a Power greater than ourselves could restore us to sanity.

3. Made a decision to turn our will and our lives over to the care of God as we understood Him.

4. Made a searching and fearless moral inventory of ourselves.

5. Admitted to God, to ourselves, and to another human being the exact nature of our wrongs.

6. Were entirely ready to have God remove all these defects of character.

7. Humbly asked Him to remove our shortcomings.

8. Made a list of all persons we had harmed, and became willing to make amends to them all.

9. Made direct amends to such people wherever possible, except when to do so would injure them or others.

10. Continued to take personal inventory and when we were wrong promptly admitted it.

11. Sought through prayer and meditation to improve our conscious contact with God as we understood Him, praying only for knowledge of His will for us and the power to carry that out.

12. Having had a spiritual awakening as the result of these Steps, we tried to carry this message to alcoholics, and to practice these principles in all our affairs.

As you can see, the Alcoholics Anonymous 12 Steps have a lot to do with seeking forgiveness (see steps in bold). Lack of forgiveness causes pain. Pain causes anger and more pain. Guilt can drive people to chemical distractions.