When Peter inquires about forgiving an offense seven times, he thinks that he is being generous, but Jesus takes that figure and raises it to the seventieth power.
That is why as sinners we are morally bankrupt. The interest on our debt is unending; it goes on forever.
Thus when God cancels our sin, it is no small matter. A cross has been raised to silence the blasphemy that forgiveness is cheap.
Instead of cheap, it is priceless; no one can pay for it. The only thing that any of us can ever do is plead mercy.