But marriage – we mean, of course, marriage as the free bond of love – is sacred in itself, by the very nature of the union which is therein effected. That alone is a religious marriage, which is a true marriage, which corresponds to the essence of marriage – of love. And so it is with all moral relations. Then only are they moral, – then only are they enjoyed in a moral spirit, when they are regarded as sacred in themselves. True friendship exists only when the boundaries of friendship are preserved with religious conscientiousness, with the same conscientiousness with which the believer watches over the dignity of his God. Let friendship be sacred to thee, property sacred, marriage sacred, – sacred the well-being of every man; but let them be sacred in and by themselves.
The point here might not be immediately obvious; Feuerbach is an atheist, of course, and he thinks religion, taken on its own terms, is inherently self-contradictory. But he thinks that there is an underlying set of anthropological truths that have been misrepresented as theology. This position allows him to propose an atheism that is (as he says) not merely negative but critical: it takes religion and, rather than just cutting it out, subjects it to critique and uses it as a set of moral building blocks. (We get some sense of how this works in practice, in a less heavy-handed way than we ever find in Feuerbach himself, in the novels of George Eliot, who is a Feuerbachian -- although, of course, she was influenced by other atheists and freethinkers as well.) So he suggests a sort of transposition of terms: morality requires taking friendship, marriage, human beings, as sacred, but "sacred in and by themselves" rather than in the derivative way he argues religion makes them. This sort of transposition (or, as I would put it, attempted transposition) is part of what makes Feuerbach very interesting reading.