Critiquing the book is not the purpose of this post. (I've not finished it for one thing.) I wanted only to write down a couple of quotes. First about Martin Luther whom the author claims considered "even our best deeds" as sins. Luther wrote of original sin as a man's beard, something we are unable to get rid of by ourselves.
The original sin in a man is like his beard, which, though shaved off today so that a man is very smooth around his mouth, yet grows again by tomorrow morning. As long as a man is alive, such growth of the hair and the beard does not stop. But when the shovel beats the ground on his grave, it stops. Just so original sin remains in us and bestirs itself as long as we live. . . . (pg. 56)
On the next page, he writes:
Prohibitions have a way of causing rebellion, at least of the covert sort. When someone says "do it my way or else" or that you cannot undertake a certain activity, it is likely you will want to do that forbidden deed even more. In our sinful condition, we never outgrow our childishness. We are like children who are forbidden certain toys or teenagers wanting more "freedom." The prohibitions of God's Law make us want what is forbidden even more. The Law is indeed the curse St. Paul said it was in Galatians 3:10-14.