I just wonder if values can only come from religious beliefs?”
The answer is “yes.” Values can only come from religious beliefs, because values are a subset of religion and religious beliefs. If you are able to conceive of values as somehow distinct from religion, then you are thinking of “religion” in a far more narrow sense than I do, and in a more narrow sense than the operational definition used by Adherents.com. There is a difference between saying, “A person can have moral values if they aren’t Catholic” (a true statement) and saying “A person can have moral values without having religious beliefs” (a non-sensical statement if one identifies moral values as a subset of religion). The Golden Rule and Wiccan rede that you mention are both religious beliefs. For some people (such as, perhaps, your atheist friend), these may be very simple yet also very significant central beliefs or operating principles. But there is nothing non-religious about such principles. These beliefs can not be explained purely by mathematically replicable phenomena. Th
