Elvis sang a song,"Don't Be Cruel" to a heart that's true. In my heart of hearts figuratively speaking,I will not harm another sentient being. I don't need a God or a law book to tell me not to or else. There is no punishment or reward for my actions. It is just right that I don't want to be treated cruel by others and so I won't treat them cruel either.
However,I'm not talking about someone who does harm to me or my family or yours. Then it is up to whatever laws there are thoughout society to measure out just punishment.
So, the basis for morality I think, lies within each and every one of us.And lies the rub,because we have different feelings on what is morality when it comes to us personally and what we experience in our treatment from others.
In closing I would say to whomever wrote those words Don't be cruel,thank you. Blueblades