We tell people to stop sinning, or they're really gonna get it. And so they obey (outwardly)...but out of fear of God's impending wrath. The Law is what makes us repent and stop sinning, and then the Gospel forgives the sin we've repented of. And then, in theory, we get better and sin less, but only out of fear of punishment. What's missing in this way of thinking is Christ, and we end up with a Christianity that is less and less dependent on Jesus and relies more on our own self-improvement efforts apart from the Gospel. But what Christ crucified demonstrates is God's love for us while we were still sinners, which leads us back to Him -- even when we sin again -- because He deals with us differently. He forgives us.