“Atheism ensures morality. Morality is a social necessity. The immorality of one disturbs the happiness of another in social relations. So checks and counter-checks maintain morality.”

Source: First as Tragedy, Then as Farce (2009), Chapter One, The Structure of Enemy Propaganda

The Need of Atheism
Context: Because morality is a social necessity, the moment faith in god is banished, man's gaze turns from god to man and he becomes socially conscious. Religious belief prevented the growth of a sense of realism. But atheism at once makes man realistic and alive to the needs of morality. Atheism alone is the surest way to morality. Those who oppose atheism in any form betray their vested interests in inequality of some kind of other.

Testaments Betrayed (1995), p. 7
Context: Suspending moral judgment is not the immorality of the novel; it is its morality. The morality that stands against the ineradicable human habit of judging instantly, ceaselessly, and everyone; of judging before, and in the absence of, understanding. From the view­point of the novel’s wisdom, that fervid readiness to judge is the most detestable stupidity, the most pernicious evil.

The Need of Atheism
Context: Because morality is a social necessity, the moment faith in god is banished, man's gaze turns from god to man and he becomes socially conscious. Religious belief prevented the growth of a sense of realism. But atheism at once makes man realistic and alive to the needs of morality. Atheism alone is the surest way to morality. Those who oppose atheism in any form betray their vested interests in inequality of some kind of other.

Athenäumsfragmente 414
Variant translations:
People who are eccentric enough to be quite seriously virtuous understand each other everywhere, discover each other easily, and form a silent opposition to the ruling immorality that happens to pass for morality.
Philosophical Fragments, P. Firchow, trans. (1991) § 414
Athenäum (1798 - 1800)
Context: If there is an invisible church, then it is of the great paradox, which is inseparable from morality, and which must be distinguished from the merely philosophical. People who are so eccentric that they are completely serious in being and becoming virtuous understand one another in everything, find one another easily, and form a silent opposition against the prevailing immorality that pretends to be morality. A certain mysticism of expression, which joined with romantic fantasy and grammatical understanding, can be something charming and good, often serves as a symbol of their beautiful secrets.

The Edinburgh Review, vol. 18 (1811), p. 121

Source: Letter from the Birmingham Jail

p, 125
Unkempt Thoughts (1957)