Substitute Nature, or even Humanity, for God, and the eternal standard of truth and holiness and goodness being superseded, every moral sentiment will be blighted and obscured.
Conscience has a relation to God similar to that which a chronometer bears to the sun.

Blot the sun from the sky, and the chronometer is useless; deny God, and conscience is powerless.

And the vices which, if not subdued, were yet curbed and restrained by the overawing sense of an unseen omnipresent Power, will burst forth with devastating fury, snapping asunder the feebler fetters of human law, and overleaping the barriers of selfish prudence itself; vanity and pride, ambition and covetousness, sensual indulgence and ferocious cruelty, will rise into the ascendancy, and establish their dark throne on the ruins of Religion.
If such be the natural and legitimate effect of Atheism on the personal happiness and moral character of individuals, we can be at no loss to discover what must be its influence on society at large.

For society is composed of individuals, and its character and welfare depend on the aggregate sentiments of its constituent members.

The question whether Atheism might not be consistent with social well-being, with the continued authority of the laws, and the general comfort of the community, is answered historically by the fact, that in modern France the Reign of Atheism was the Reign of Terror, and that in ancient Rome its prevalence was followed by such scenes of proscription, confiscation, and blood, as were then unparalleled in the history of the world.