Imagine the following: There is in fact a god or gods. This deity or committee of supernatural beings in fact created the universe, is omnipotent or peri-omnipotent, and has decreed a set of rules for humans to follow. What are these commandments? Well, among the most important ones are: be caring toward others, be fair and just and compassionate, and treat other sentient species with respect. While you are here on Earth you are assured that you will not be punished for any transgression. Neither will you be rewarded in this life for following The Law to a tee.
And oh yes, one more thing. This god/committee has decided that after you die, that's it. You're dead and are no more. Forever. In other words, there is no afterlife. No paradise, no happy hunting grounds, no harem of six dozen virgins awaiting you on the other side. And no hell of any sort either. Once you've kicked the bucket and are six feet under, the gods make certain that bacteria and worms see to it you are irrevocably obliterated.
Now ask yourself, Given that you know with absolute certainty that there is no divinely-caused punishment (nor reward) in this life and that there is no hereafter, would you then go about leading a life of crime? If you're a young man, would you suddenly appoint yourself as the alpha male and ravage every teenage female you run into? Instead of queuing up in a bank to withdraw from your account, would you cut in front of the line and announce a heist? Would you carry around a sword and summarily hack every guy who gets your goat? Would you let your ego become the emperor and allow it rule absolutely?
In educating our children our goal is not teach them to be good only because there's a reward in the offing and to avoid evil only because punishment awaits them. While we employ the carrot and stick with the very young, we eventually want to impart to children the habit of doing good for goodness sake, and to avoid evil because it is bad. We also yearn and hope that in time they do good and avoid evil not because we've commanded them, not because rules, regulations, and laws tell them to do this and not do that, but again because it is good to do good and harmful to do bad. We want our descendants to begin by learning the letter of the law but graduate to understanding the spirit of the law, cherishing it, incorporating it into their very being, and becoming persons who have the ability for ethical thinking and judgment. We want them to be able to think and judge for themselves what is right and what is wrong, and take the appropriate action.
Now there are not many religions that foster such a formation. Buddhism is among the few that easily comes to mind. We need only remind ourselves what the Buddha advised his disciples: "Do not accept what you hear by report, do not accept tradition, do not accept a statement because it is found in our books, nor because it is in accord with your belief, nor because it is the saying of your teacher. Be lamps unto yourselves" . You will also find it being fostered in strands of various religions including liberal Christianity. But you will be hard pressed to find it in most mainstream religions, not least because most religions and denominations guard the orthodoxy, are dogmatic and doctrinaire, and are authoritarian in nature. Such conditions necessarily lead to the polar opposite of maturation, independence and self-reliance. Indeed, the ability to unfetter oneself from authority and tradition and then think for oneself is frowned upon, discouraged, and at times even sanctioned.
Needless to say those who are unaffiliated with any religion (or are adherents of religions that have no ethical dimension, i.e., have no moral prescriptions/proscriptions or offer no criteria for ethical decision making) must perforce search for and choose their own ethical system and must actively use their minds in this endeavor. In being on one's own, there is no guarantee or implication that one will acquire excellent ethical judgment skills or that one will be ethical. Nevertheless, there is that freedom to be able to think for oneself and to be eclectic and learn from any and all sources.
Huston Smith, The World's Religions: Our Great Wisdom Traditions, Harper San Francisco, 1991, p. 94.