If I'm a law abiding person, why should I care what law it is ? If I don't steal, why should I be afraid of the authority cutiing my hand ? If I don't commit adultery, why should I be afraid being whipped or stoned (?)
Syariah, civil or whatever terms all are just a manner of implementation. It all comes base on the 10th commandments. Murder is a sin, how we convict a murdered (if proven guilty) is up according to our implementation of the law. Whatever law we choose, for example murder is wrong, or sin even if we use Civil American law, UN law, Syariah, common law...
So what's the big deal with it ?
Our common civil law now for example. A person who robs maybe get a jail term of 2 years. After he got out he has 50-50 of either going to rob again or turn a new leaf.
I believe whtever law we use, if it's practical and it stops crime then it's a good law. Maybe if the US uses syariah law the the prisons there wont be highly populated as of now. Maybe.
