Religous persons often use argument that how can be a person moral without belief in God which means, to them God is the only origin of morality. Lets consider what other origins of morality can be.
Rouesseou in his Social Contract says that Law is infact weapon of rich to protect their property from hungrey eyes of poor while Morality is a weapon of week to protect them against the stronger in the society.
Marxist argue that tools used by society shape up the structure of society and alongwith that its morality.
We may or may not agree with the above but one thing is quite evident that morality originates from social needs. It is an unwritten social contract between members of a society. Sort of code of good and bad for members of society to enable them adopting ways of life benifical to society volanterily(without being forced into).
Hence morality originating from social needs is viable to change as social needs change. For example we find morality of industrial society quite different from that of agricultural society of past with exception of universals applicable to all societies. It may also vary society to society in the same age.
What you think other potential origins of morality can be?