Law and Religon

If law became influenced by religion in the sense that laws were changed and “reshaped” in order to satisfy or abide a specific religion; I believe that any society would become a chaotic mess. First of all, there are many religions to take into consideration, and if a society or government would especially pick one religion above all – this would cause many conflicts and possibly wars among the society. Correct me if I am wrong, but religion has been the primarily catalyst for some wars starting from the crusades to the current radical Abrahamic religious customs. Many individuals have killed other human beings over their beliefs on a specific religion, or to satisfy their particular religion. For example, the Nazi party decided to prosecute, incarcerate and later kill any individual of Jewish decent. They were solely prosecuted and killed due to their religious background. Killing a human being over a belief that cannot even be proven is simply absurd. My question is the following: Why would a society incorporate religion and law as one? Individuals have already a hard time abiding by the law – now add religion to the equation. It does not look too good, does it? I believe that laws should be like mathematics – universal. Universal in the sense that everyone in a society knows the difference between wrong and good for the most part – certain customs may differ. In short, I believe that religion should stay away as far as possible from the legal system at all cost. Individuals have fought over religion and beliefs for thousands of years; let’s not give them another motive to fight.