They say that He held out empty terrors to deter them from sin. We answer, if He threatened falsely to check unrighteousness, then He promised falsely to promote good conduct. Thus while they go out of the way to prove God merciful, they are not afraid to charge Him with fraud. But, they urge, finite sin ought not to be visited with infinite punishment; we answer, that this argument would be just, if the righteous Judge considered men’s actions, and not their hearts. Therefore it belongs to the righteousness of an impartial Judge, that those whose heart would never be without sin in this life, should never be without punishment.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).
Also cites: Mor xxxiv, 19