And everyone has to forgive countless offenses pretty much every day. Those of us with small children and human husbands for sure. And anyone who works in retail. Probably anyone who comes in contact with any other human on a daily basis, actually. We are all sinful, and sinners therefore... sin. Against each other. Competing world views, competing objects of worship.
Here are some resources that I've personally found to be very helpful in forgiving as the Lord has and continues to forgive me:
1. "Gospel Forgiveness," an article by Tim Keller- I have an article by this title, but couldn't find it online. I did find it in its entirety (minus an introductory paragraph) as part of this marriage conference handout from Tim Keller's church, Redeemer Presbyterian: http://download.redeemer.com/
pdf/Love_and_Love_Language.pdf It starts on page 11 with "A. The Resources for Forgiveness." Wonderful super-helpful stuff. When I was in counseling in college, I gave this to my secular counselor (who was a believer, but had never heard of using the Scriptures/Gospel to deal with problems), and I think it really opened her eyes. She was blown away by it... I hope it changed the way she counseled people! I've wondered if one of the Lord's purposes in bringing me into her office might have been to expose her to the idea of Gospel-empowered forgiveness. I guess One Day I'll know!
2. "How to be Free from Bitterness," an article by Jim Wilson- I have this as a little pamphlet, but now it's being sold as an actual book!
I'm not sure about the other articles in the new format, but if they're as helpful as the original article is, it'd be well worth the purchase price.
3. "Forgiving Grace," a sermon by Tim Keller- That whole sermon series ("Practical Grace: how the Gospel transforms character") is life-changing. SO worth the price of the download (I think Keller should make the manuscripts of the series into his next book!). The analogy of forgiveness as "paying down the debt of pain" yourself instead of making the other person pay captured my heart and has helped me so much.
4. Unpacking Forgiveness,a book by Chris Brauns- I did a cursory read-through of this book while spending a week with my best friend & her husband (a pastor), and really liked it. My pastor friend likewise recommended it. It's got some great help for thinking through what forgiveness actually entails and addressing the question of forgiving without the offender repenting vs being ready to forgive should they ever repent.
5. The Peacemaker, a book by Ken Sande- as Christians, we are called to go beyond merely not being bitter; we're called to help make peace! My parents' church did a Sunday School class on this, and I sat in for 2 sessions while visiting. It was really good stuff! Very applicable, balanced, and eye-opening. Another church dear to my heart did a children's VBS based on this book last summer. If you want a way to teach your children how to forgive and sort through arguments, I suggest the kid's version of this material: The Young Peacemaker.