Sauron had not served Morgoth, even in his last stages, without becoming infected by his lust for destruction, and his hatred of
God (which must end in nihilism). Sauron could not, of course, be a “sincere” atheist. Though one of the minor
spirits created before the world, he knew
Eru, according to his measure. …
Sauron was not a “sincere” atheist, but he preached atheism, because it weakened resistance to himself (and he had ceased to fear God’s action in
Arda). … But there was … the effect of
Melkor upon Sauron: he spoke of Melkor in Melkor’s own terms: as a god, or even as God. … His cunning motive is probably best expressed thus. To wean one of the God-fearing from their allegiance it is best to propound another unseen object of allegiance and another hope of benefits; propound to him a Lord who will sanction what he desires and not forbid it. …