And that contradiction is evidence of serious flaws in religious moralities.
For me, a rational ethics -- free from religion -- is the only morality worthy of that name.
Aristotle produced a simplistic rational ethics based on virtues visible in respected people, and vices visible in non-respected humans. And teaching Aristotle's non-denominational ethics in public schools would be a great idea, but ... We'd be turning out individuals with the same moral upbringing of Alexander the Great, and that wouldn't do in a liberal world.
Even better is Ayn Rand's ethics. Her's is an ethics metaphysically based in reality and epistemologically based in reason; making it a clear and concise rational ethics that makes sense. Ayn Rand's ethics is clearly also what America's founding fathers had in mind when writing the founding documents that recognized and moved to preserve individual freedom -- the Declaration of Independence, the U.S. Constitution, and the Bill of Rights.
Then Aristotle didn't "produce" it, but merely "described" it. The morality was already on display, so that people could be categorized into "respected" and "non-respected". Man doesn't produce moral law, he struggles to obey it.
Even those who deny the source of moral law, rather than wallow in immorality, inconsistently argue that they're as "moral as everyone else".
What are you going to do when you've based your morality on Ayn Rand, and someone comes along who doesn't believe in Ayn Rand's morality? Are you going to force your morality on him, or appeal to a higher authority?
I know, I know - anyone as intelligent, rational, and clear-thinking as you would know that it is irrational to disagree with you, since through pure reason you have found pure truth.