+ Positive Mitzvah
Judge laws of buying and selling according to Torah requirements.
As we know there are situations that arise where transactions between seller and buyer are valid and situations where they not.
We have an obligation to judge these according to Torah laws.
There is a special Mitzvah regarding this specifically “If you sell anything to your neighbour/friend or buy from your neighbour/friend…” Vayikra 25:14
Commerce is constant with people and it is impossible for humanity to exist for even one day without it.
Land is acquired by money, document or demonstration of ownership.
Movables and animals are acquired by pulling and more so by lifting up.
This applies everywhere in every time.