General Theory of Religious Ethics

At the end of my Religion and Ethics class last semester, we were asked a single question, "Can you have ethics without religion." The answer is obviously, yes, you can; we are innately ethical beings with an inherent sense of morality and the cognitive and behavioral tools to apply it. However, the question actually asks something much deeper. If religion is not a necessary component of ethics, then what purpose does it serve for developing and applying an ethical understanding? Next, how does the fact that religion can be a source of ethics shape our understanding of ethics in general?

I was originally going to write as much as I wanted here, but it makes more sense to do it in separate posts.