Willingness to assume another's sin is an expression of sinlessness. To be Christian means to be like Christ, and what Christ did was take responsibility for all of the imperfection and sins of everyone that would come to mortality. By owning our sins, He owns our salvation. He gives it to us as we repent.
As He is the Author and Finisher of our salvation, we must work out our salvation with fear and trembling before God. We are at His mercy. In this position we are told by God to forgive all men. Since we are at the mercy of God, we aren't in a position to withhold mercy from others. If we seek justification by our obedience, we are fools because there are none that are perfect and thus no one can claim that they are deserving but God is merciful.
The Lord has made it possible for all to be forgiven, so when we withhold our forgiveness, we are saying that someone is unworthy of it. By what grounds do we have to with hold forgiveness? Let he that is without sin throw the first stone. We cannot judge others as anything but Christ Himself, as He said that what we do to the least we do it unto Him. So, when we withhold forgiveness we are withholding it from Christ, even though He was perfect, He still pleads with us to forgive all men as if it were He who was responsible for their sins, because He is, as the Lamb of God a sacrifice for the sins of all.
We lose ourselves if we save ourselves. If we withhold charity to others, we are withholding blessings from ourselves. It is liberating to forgive. Carrying the burden of a bitter grudge can only weaken our hearts because we are sinning when we don't forgive and sin keeps us from God which means we are ensnared by Satan. Ensnared by Satan means we are following Satan and thus nonredeemable by Christ as He won't force salvation upon us. Numbered among Satan means we have the total weight of our sin upon ourselves, instead of Christ. We must then suffer as Christ suffered for Mercy cannot deny Justice. Leaving Christ means leaving Mercy and thus left to suffer under the law which we broke and it is just as we are all sinners. Christ pleads with us to come unto Him so we can avoid hell and Justice. As he satisfied the demands of Justice by being the great sacrifice, He can offer us Mercy and salvation.
The second most important commandment is to love others and as we break it by being unforgiving that makes us guilty of a greater sin than whatever trespass against us. No grudge or trespass against us is more valuable than keeping the first and second commandments of God, which simply say to love and serve.
This also means we shouldn't think ourselves beyond His capacity to forgive. We need to forgive ourselves as much as others and seek favor with God. That is how our peace
comes.
