To begin, I never realized the Ten Commandments were called the Decalogue. However, what really caught my attention is that Collins explanation about some of them not necessarily dating back to Moses' time. The one that I picked up on was "You shall have no other God's before me" (Exodus 20:3). Collins shared, on page 83, that "...prophets in the ninth and eighth centuries who demanded the worship YHWH alone seem to have been a minority". It leaves me questioning exactly how pieces together the Old Testament truly is and why certain ones were added later.
I am not familiar with the name for The Book of the Covenant. These laws are different from the Decalogue in that they are if, then statements. The interesting piece was the final law Collins explained, on page 87, which is the law that Jews use to explain why they must keep meat and dairy separate. This was interesting because I've never really understood some of that reasoning.
The Ritual Impurity Laws (Leviticus 11-15) were interesting in that the title is a perfect fit. It is a slew of actions to help people remain clean through things like dietary and bodily issues. The discussion Collins shared, on page 95, in regards to explaining why certain animals were unclean was intriguing. Scholars are still trying to decipher why, ethical reasoning or fear of the unknown. The law in regards to purifying after childbirth was a section that stood out. I assumed it was due to sinfulness through childbirth. There are differences between having boys and girls, but this cleansing wasn't due to sin. These laws are ritual which, according to Jonathan Kiawans, are not typically sinful in nature.