He himself bore our sins in his body on the tree, that we might die to sin and live to righteousness. By his wounds you have been healed. (1 Peter 2:24)

What is the basis of our not holding grudges against Christian brothers and sisters who repent?

Our moral indignation because of a terrible offense done against us does not evaporate just because the offender is a Christian. In fact, we may feel even more betrayed. And a simple, “I’m sorry” will often seem utterly disproportionate to the painfulness and ugliness of the offense.

But in this case we are dealing with fellow Christians and the promise of God’s wrath against our offender does not apply, because there is “no condemnation for those who are in Christ Jesus” (Romans 8:1). “God has not destined [Christians] for wrath, but to obtain salvation through our Lord Jesus Christ” (1 Thessalonians 5:9). It looks like they are going to get away with it!

Where shall we turn to assure ourselves that justice will be done — that Christianity is not a mockery of the seriousness of sin?

The answer is that we look to the cross of Christ. All the wrongs that have been done against us by genuine believers were avenged in the death of Jesus. This is implied in the simple but staggering fact that all the sins of all God’s people were laid on Jesus. “The Lord has laid on him the iniquity of us all” (Isaiah 53:6; 1 Peter 2:24).

The suffering of Christ was the real punishment and recompense of God on every hurt you have ever received from a fellow Christian. Therefore, Christianity does not make light of sin. It does not add insult to our injury.

On the contrary, it takes the sins against us so seriously that, to make them right, God gave his own Son to suffer more than we could ever make anyone suffer for what they have done to us. If we go on holding a grudge against a fellow believer, we are saying in effect that the cross of Christ was not a sufficient recompense for the sins of God’s people. This is an insult to Christ and his cross you do not want to give.