Put on then, as God's chosen ones, holy and beloved, compassionate hearts,kindness, humility, meekness, and patience, bearing with one another and, if one has a complaint against another, forgiving each other; as the Lord has forgiven you, so you also must forgive. And above all these put on love, which binds everything together in perfect harmony. ~ Colossians 3:12-14
How can we forgive as God has forgiven us? I don't know how to do that without embracing the message of the cross. The cross means, at the least, that #1) God so hates evil and injustice that he is willing to come suffer himself in order to end it; but #2) We are so tainted by evil as well that Jesus had to die so that we could be forgiven. Both of these truths are absolutely essential the Gospel of forgiveness and reconciliation. Miroslav Volf puts it perfectly:
Forgiveness flounders because I exclude the enemy from the community of humans and exclude myself from the community of sinners. But no one can be in the presence of [the Cross] for long without overcoming this double exclusion....When one knows that the torturer will not eternally triumph over the victim, one is freed to rediscover the torturer's humanity and imitate God's love for that person. And when one knows that the love of God is greater than [my] sin, one is free to see oneself in the light of the justice of God and so rediscover one's own sinfulness. (Volf, The Spacious Heart)
Rob Bell recently preached a great sermon on the Lord’s Prayer and Forgives.