The scandalousness of God’s indiscriminate forgiveness hits us even harder when we are called on to imitate it. When we need to forgive, most of us, perhaps unconsciously, feel entitled to draw a circle around the scope of forgiveness. We should forgive some, maybe even most, wrongdoings, but certainly not all.
Maybe we think unintentional offenses are forgivable, and deliberate ones are not. But how would we draw the line? How intentional would the offense need to be? If the offense were truly unintentional, there would be something to be sorry about but nothing to forgive; it was just an accident. Or maybe we think small offenses are forgivable, and horrendous ones are not. But again, where would we draw the line? An offense is an offense and has as much right to be forgiven as any other, which is no right at all. No line separates offenses that should be forgiven from those that should not. There are no unforgivable sins.
— Miroslav Volf, Free of Charge, p. 178-179