Text 28 Deuteronomy 19-26

Deuteronomy 20-26 http://www.biblica.com/bibles/chapter/?verse=Deuteronomy+19&version=niv

These are laws governing community life--  Some laws are interesting for example laws governing war (20:1-20), care for men and their families (20:5-10) and even trees (20:19-20). What are the recurring themes in the laws?