Galatians 3:10-13
All humankind should be under a curse. Even though God's law promises a path to heaven, its demands are too great for anyone to achieve: constant faithful perfection.
On Good Friday, Jesus offered himself as the sacrifice to pay for all of our failures to achieve perfection. He willingly took the curse that we had earned on himself, for no other reason than his love.
Now, instead of living under a curse, we live at peace with God, not because of anything have ever done or could ever do, but simply because Jesus offers us the peace he earned.