Morality is the intent to achieve good, and to achieve it for others as well as for ourselves. Ethics is the pursuit of the best rules, those that will most likely achieve the best possible results for everyone.
To see the distinction, consider the Jewish family of Anne Frank hiding in the attic during Nazi occupation. The soldiers knock on the door and ask if there are any Jews. It would be unethical to lie, but it would be immoral not to.
We call something “good” if it meets a real need we have as an individual, a society, or a species. A “moral good” is actually good for us and benefits us in some way. A “moral harm” unnecessarily damages us or diminishes our rights in some way.
Morality seeks “the best good and least harm for everyone”. Moral judgment considers the evidence of probable benefits and harms to decide a course of action. This judgment is objective to the degree that the harms and benefits are easily observed and compared. But the ultimate consequences of a decision are not always known. Two good and honest individuals may differ as to what course of action will produce the best result. A democratic decision can be made to determine a working course of action, which can be further evaluated based on subsequent experience.
Ethics are about rule systems. Rules include customs, manners, principles, ethics, rights and law. When one speaks of “morals” or “moral codes” one is usually speaking of ethics. But morality is not the rule, but rather the reason for the rule, which is to achieve good.
Throughout history, rules have changed as our moral judgment evolved. Slavery was once permitted, but later outlawed. The equal rights of women to vote was established. The right to equal treatment without regard to races, gender, or religion was established.
Different cultures may have different rules. But all rules move slowly toward the same goal, to achieve the best possible good for everyone. And, to the degree that moral judgment is based in objective evidence, all variations are moving toward a common, ideal set of rules and rights.
In Matthew 22:35-40, Jesus was asked, “What is the greatest principle?”, and Jesus said the first principle is to love God and the second principle is to love your neighbor as you love yourself.
A Humanist translation would be to love good, and to love good for others as you love it for yourself.
But Jesus said one more thing, “On these two commandments hang all the law and the prophets.” In other words, this is the source, the rationale, the reason, the “Why?” behind every rule and every right. It is the criteria by which all other principles, ethics, and rules are to be judged.