Your writing could be a little more clear if you put some effort into it.
If a church is to make the law, for instance in telling the military who is married and who is single among it’s ranks, then which church makes the decision, the Episcopalians or the Catholics?
Now a particular church making a civic law is expressly forbidden in the first amendment and in violation of the principles of jurisdictions found in the Bible. Law is based on religiously held tenants, not not by sectarian institutions. But to your other point, civil law is doomed to failure when it attempts to legislate against reality. This is the current failure of our current unicorn economic policy, anti-family law and regulation that attempts to force a work-around of physics. Only working in harmony with God's laws, might a society reasonably expect to prosper and thrive.