What loophole did God give for the death penalty?
God's loophole is the substitutionary death of Christ: although every sinner must die because sin's penalty is death, a person need not die in himself. Christ's death can be taken as his substitute. By simply believing the gospel, Christ's death takes the sinner's place.
Les explains that God first established a fundamental law: the day Adam ate of the tree, he would surely die, and Scripture says the soul that sinneth shall surely die. Paul confirms all have sinned and come short of the glory of God, so death is mandated for every son of Adam, and there is no getting around it. But God provided a loophole: we have to die, yet we do not have to die in ourselves, because we can take Christ's death as our substitution. If we simply believe the gospel, Christ's death takes our place—the substitutionary death of Christ. That is why Paul teaches the old Adam must be crucified and put to death, and he that is dead is freed from old Adam.