"He could see a deep sadness in her eyes. I am not who you think I am, Mackenzie. I don't need to punish people for sin. Sin is its own punishment, devouring you from the inside. It's not my purpose to punish it; it's my joy to cure it."

Some would say that it IS God's will to punish sin in all its forms. Sin is lawbreaking and there is always a penalty exacted otherwise the law is without effect. Without the threat of punishment the Gospel loses its saving impact. I mean why would we need a Saviour from sin's penalty if there was no punishment?  (see Prodigal Magazine review on the problems with the theology in The Shack). So I take issue with Young's softness on sin if that is what he is trying to do here.

BUT I don't think that is what Young is trying to do with this exchange. He is dealing with a perception issue on the part of MacKenzie.

Later, we discover that Mack's big question is NOT does God punish sin BUT is God GOOD?

And if God is good HOW do I know that given my awful life experience especially given the loss of a child.

That is what is at issue in the book. It is the age old question - how can a GOOD GOD permit BAD things to happen to GOOD people?