I just finished a very good book which in one chapter illustrated how morality arose and endures in humans. This book stated that morality has three bases:
1.Culture.. (of which religion is only one domain)
Culture: humans learn and share by being members of a society. Culture includes knowledge and skills, beliefs, norms, values, morals, etc.
Christianity, being more about belief and faith, have little to do with works and morality. How many of the morals existent in the New Testament are really useful? Even so, the existence of a moral code in Christianity is far from being actual morality as is evident by the high rate of crime, deviance, and antisocial behavior committed by Theists.
The book states that morality, in the sense of standardized and restrained behavior, is actually a natural, evolution based phenomenon.
Reason itself would lead to standardized and socially beneficial behavior on the basis of principle and intersubjectivity (the awareness of the feelings of others) the author asserts. No religion is needed to tell us that killing is destructive to other people, to us, and social order. Reason can and does proceed to most of the morals presented in the great religions without the need of a god, spiritual rewards, or punishments.
Indeed, when atheists adhere to good behavior based on ethical principle, without a threat of punishment or promise of reward, it can be argued that atheists are more moral than theists.
A God is unnecessary to morality.