The faithfulness of God in forgiving us requires our faithfulness in forgiving others.
I'm stunned by the description of God in 1 John 1.9. If you've been around church at all, you've encountered this verse: "If we confess (say the same thing about) our sins, He (God) is faithful and just (righteous - same word in the Greek) to forgive us our sins and cleanse us from all unrighteousness."
Maybe I'll take tomorrow and talk about how God is righteous or just in forgiving sin, which is completely counter-intuitive. Imagine us calling a judge "righteous and just" if he let a guilty person walk on a murder charge.
But today, faithfulness. I love God's faithfulness to me and to my family. We have many stories of it: God providing for us when grad school was happening and we were broke, God giving us jobs we loved, God taking care of the places where we lived, God making ways for our children to get what they needed when it didn't seem possible. I could go on and on. For some of our family's stories, you can check out my beautiful and amazing wife's blog: 4uRuthie. She's a much better writer than me anyway.
But thinking about God's faithfulness in light of my sin is something else. What that verse promises is that every time I come to God to deal honestly with my sin, I am met by a faithful God who forgives me. Even when it's the same sin over and over again. Even when it's heinous and horrible. Even when it's secretive and silent. He's faithful to forgive. Amazing. Stunning. Wow.
And about the only reason we would come to God and not receive forgiveness in that moment is if we didn't come and deal honestly with our sin. It's not the saying of the words that prompts His faithful forgiveness. It's our taking the same response to our sin as He does. But even when we come to Him and deal honestly and openly, it's not our act that secures our forgiveness. The reason God is faithful to forgive is because Jesus Christ, His Son, died on the cross as a propitiation for sin - a sacrifice that bore God's justified wrath and accounted to us His right-standing with God.
Last thought: these sorts of things in the Bible always prompt an ethical question in me - what am I supposed to do with this? The answer: faithfully forgive others, just as God in Christ has forgiven me (cf. Ephesians 4.32). To remain unforgiving is in itself a sin and puts us out of step with God and His Kingdom - making us in need of that very same forgiveness we're refusing to extend to others, something Jesus said will keep us from experiencing the forgiveness God has for us (Matt. 6.14-15).