Along the lines of the 4th post, I'd defend the notion that morality derives from community. This is true in communities where there is a shared religion as well as in communities of diversity and/or no religion at all.
We see this as being the case when different societies adhering to the same religion develop different dogmas and rules of behavior, despite possessing what might be seen as a shared belief system.
This is an important idea because it means that people are both capable of and responsible for shaping the rules and codes of conduct within a community. The ramifications here are practical, legal, and political. This point puts me in mind of the famous Gandhi quote: Be the change you want to see in the world.
It's up to us, as communities, to decide what is right, wrong, acceptable and unacceptable. Whether we refer to holy books or not, the responsibility for any and all moral codes rests on the people of the community (as interpreters of religious doctrine or as free thinking individuals; it's all the same).