By grace we're created in the image of God. When we corrupt our lives with sin, the grace of God in Jesus Christ forgives us and makes us fully alive again.
Christ "has broken down the dividing wall. . . . that he might create in himself one new humanity in place of the two, thus making peace, and might reconcile both groups to God in one body through the cross, thus putting to death that hostility through it."
A common tendency among believers is to think of Jesus Christ in the past tense. He's the guy we study in the Bible that some taxidermist must have mounted on a wall.
The gospel is the good news that Christ's death and resurrection--mediated through scripture, tradition, and the sacraments of the church--offers new life for all who embrace it.