It is easy to see why Martin Luther said this book and Bondage of the Will were his favorite. This book breathes typical Luther, but also has the gain of being largely practical. The bulk of the book covers the ten commandments and the Lord's Prayer.
The Luther we get in this book has his attacks on the papists, but he is much more positive here than elsewhere and spends much less time attacking his opponents. In particular his coverage of the ten commandments reminds me a lot of the bits of the WCF that I have read.
So, I don't have time for a full review, but here are a few gems:
-The Sabbath does not strictly carry over from old to new covenant. We worship and rest on Sunday because of good order and natural law, not divine positive law.
-Luther has a convicting chapter on the duty children have to their parents. He, of course, makes the duty broader (we are to honor magistrates and elders as fathers), but the narrow command of honoring the ones who begot you comes home really sharply.
-An equally convicting section on being careful not to ruin your neighbor's name. Luther makes the careful point that there are some public faults that can be censured just fine (he uses the example of the Catholic church's public sins), but he still is much more strict than we are.
-We have a duty to pray. We are to call for God's will to be done, even though God is already making sure that his will is done. We must still participate. Luther says we have so many needs that we aren't even aware of, and we must not hesitate to pray for them. Encouraging.
-Luther makes the point that we come to the sacraments because we are sinners. I am not persuaded of his way of viewing baptism and repentance as all the same thing, but his heart is clearly in the right place: baptism is meant to reassure those who have faith.
There's lots more and maybe someday I will sit down and read it. The audiobook on Canon Plus has too much music, but I liked the reader.