By Rabbi Nancy Morris, August 24, 2009
The parashah of Ki Tetzei contains the largest concentration of mitzvot of any portion. One of these is the basis of the law of negligence. In Torah times, houses had flat roofs which could often be trod upon by animals or people. A parapet would be a simple way of ensuring that no one fell off the roof.
A key element of negligence law is proving a duty of care between the parties involved. What is so novel about this Deuteronomic law is that the Torah recognises any owner of a new house to have a duty of care to ensure the safety of any visitor to that house.