What makes morality?
Is the pious loved by the gods because it is pious, or is it pious because it is loved by the gods? - Plato, Euthyphro
... everything which [God] wills must be held to be righteous by the mere fact of his willing it - John Calvin, Institutes of Christianity
if God does not exist, everything is permitted. - Ivan, in the Brothers Karamazov, by Dostoyevsky.
Growing up in a protestant Christian philosophical tradition and culture, downstream of Calvin's belief on Plato's question, morality was defined by God. Good actions, by definition, were those that were approved of by God. This is known as divine command theory, and was the belief of a lot of foundational thinkers in Protestant theology.
Vertical Morality
I'll be referring to this sort of top-down morality as vertical morality. In vertical morality, authority creates the boundary of what is right and wrong. Murder is a sin against God, first and foremost. Poaching deer in the king's forest is an offense against the person of the king. Failing to worship the Emperor is a slight against is name.
In vertical morality, the seriousness of your offense is directly proportionate to the majesty, worth, or excellence of the one you offend. This often correlates with their perceived power.
It is this sort of logic that has the conclusion that the smallest possible white lie deserves an eternal period of torment.
... if I say to God, "I'm going to do this against you"—this small sin, say, spitting on somebody... you've said no to God... every sin, from the smallest to the greatest, is against God and not just against people and their consequences. And in that sense every sin is infinitely heinous. - John Piper
To which I say, fuck that conclusion. Imagine a two year old (or fifteen year old, if it makes a difference) child who tells a single white lie, and then gets flattened by an eighteen wheeler. Under the logic of vertical morality, not only did the child deserve to be spattered on the pavement, but they also deserve to be raped, flayed alive, and then slowly killed. And all of that, according to a Christian doctrine of eternal hell, is infinitely better than actually going to hell.
If you believe in the idea of hell as a punishment for "sinners", do not glance away from that consequence. Pause. Roll it over in your mind. Would you torture a child for a single moment because they lied to you? How hot would you heat the pincers?
Of course you wouldn't - you're not a monster. Are you better than the Christian god? Are you more merciful, or more forgiving?
Horizontal Morality
If we don't get a barrier between right and wrong from an authority figure, where do we get it from? We can get it from an obligation to treat other beings with respect for their wellbeing and autonomy. We can treat them as we want to be treated (or perhaps as they would want to be treated).
"But that's not an objective sense of morality!" Sure, I concede that. I have no knowledge of a universal sense of ethics inherent in the universe in the same sense that F = ma, or 2 + 2 = 4.
But we both agree, right? There may be some alien race with a very different view on morals, one that we may find repugnant. And Ted Bundy or Genghis Khan might disagree that they have an obligation to treat their fellow man with love. But so much the worse for the Khan!
Morality may not be objective. It may be nothing more than you and I looking each other in the eyes, seeing each other's humanity looking back, and mutually cherishing that. But that doesn't mean it's worthless. If we both look at a great work of art by Monet or Banksy, we can't measure it's beauty in pounds, or ounces. But we can feel the glow within, and appreciate it nonetheless.
Rather than viewing morality as law from above, perhaps we'd do well to view it as a piece of art we are all painting, day by day.