Many theists believe it is clear-cut. Humans can only have opinions about morality, and no one’s opinion is any more valid than anyone else’s. This leads them to the conclusion that an objective source of morality must stand apart from, and above, humans. That source, they say, is God. Since atheists, reject God, atheists can have no basis for morality.
This is really two separate arguments: (1) that God is the source of objective morality and humans can learn morality from God and (2) that humans on their own have no way to know what is moral and what is not.
Can atheists be moral? - Atheist Alliance International
An interesting subject, but I really don't understand that Greek(?) separation of morals and ethics, wouldn't know from where to approach.
My view is simple - there's truth beyond expression every soul, spirit agrees and yearns too.
Finding out and knowing, bringing the truth to consciousness is nothing if You don't act on it.
So there's actions (Mitzvah) and purpose, or as in Hebrew "the taste" of the action.
I come from a more holistic, Jewish, Jungian, Zen...duality in all of its expressions of atheism vs religiosity, morality vs crime, are insincere and infantile in a sense, it's all one truth of one reality. Don't confuse the finger pointing to the moon with the moon itself kinda thing.
Anyway too broad a subject for me, but if someone wants to spend time on the subject,
I suggest watching this exquisite exchange between these truly outstanding minds, discussing specifically the morality and ethics of modern culture from 2 different perspectives: