The second of five realities rising from the holiness of God, according to David Wells, is that There Is Sin. This is a reality we lose when we fail to see God as the “outside God.”

The second consequence is that without the holiness of God, sin loses all its meaning. Sin, as I have argued, is not simply the breaking of some church rule but is every act that is an affront to the character and will of God. It is true that only 17 percent of Americans define sin in relation to God, but their mistake in no way diminishes the nature of what their sin is.
   What has been lost is not the sin itself but its culpability. Sin in all its forms is still present in life. It is still trailed by all the pain and confusion that always attends it, but it is not being understood in relation to God. It thus loses its depth, character, and culpability because we have lost our internal compass. That compass lines up our sinning, not merely horizontally, but also vertically. Sin brings not only shame, but also guilt when we understand it in relation to God’s holiness. “Against you, you only, have I sinned and done what is evil in your sight” (Ps. 5:14), after the calamity he brought upon himself by his sexual affair. Only then do we understand its nature. When we lose the holiness of God we have sins pains and calamities, but we do not understand it anymore.
   But if we begin to see the nature of sin, we are on the road back to reality. We are on our way back into the presence of God through Christ. It is not that the knowledge of sin alone suffices, but rather that it pushes us to seek our deliverance from it. Knowing about sin is therefore vital knowledge. There is none quite so lost as those who know little or nothing of their sin. Knowing about our sin, therefore, is something for which we should be deeply grateful. This is why it is so important for us to be able to understand that God is not simply the inside God but he is the outside God as well.

—David F. Wells, The Courage to Be Protestant: Truth Lovers, Marketers, and Emergents in the Postmodern World (Eerdmans, 2008), 128.