God commands us to love, and not hate.

That’s reason enough to leave off hatred.

But You should avoid hating for selfish reasons, too. Because hatred is a vice that does nothing to the one who is hated (although terrible things can happen from the mind that hates).

But fundamentally, hatred poisons the mind and heart and soul of the hater.

Let go of your grudges and malice and ill will to others. Do it because you’re commanded to do so. But do it also because it’s good for you. Love your neighbor, even (or especially) those who are unloveable. And make your life better, too. Hatred is a poison that you don’t need.