When Paul tells us that Jesus died for our sins, when he says of our Lord in Colossians that in Him, we have redemption, the forgiveness of sins, he’s not saying that we, as Christians, are off the hook for the pain and sorrow we’ve inflicted and will yet inflict on others. He’s saying that, as Christians, the debt we owe God has been assumed by God Incarnate.
When Jesus cries out from the cross “Father, forgive them!”, the forgiveness He is referencing is not for the behavior of the onlookers towards each other, but for their behavior towards Him, the Son, who is God Incarnate.
This cannot be emphasized strongly enough. Unless the concept of harm to others is allowed this dual consequence, the embrace of Christ’s sacrifice threatens to dissolve into libertinism. That is Paul’s great concern in Romans 6. The reconciliation that Christ achieved for us is a reconciliation with God, not with those we harm. That reconciliation remains our human responsibility.
Jesus tells us as much when He separates offerings at the alter from reconciliation with one’s neighbor, and says the former does not obviate the latter. He says it in another way when he instructs His disciples to let their light shine before men, and then immediately adds that He did not come to eliminate the requirements of the law. (Matthew 5: 16-17)
The way human obligation reaches into the spiritual realm does not eliminate its worldly meaning or even reduce it one jot. On the contrary, it is the divine reverberation of our sin that gives its worldly manifestation eternal weight and significance, that gives it more than human anchorage, that is a consequence and responsibility of our own – however undeveloped – divinity.