please help A christian has stumped me on this one.

[Angrboda]

"The various modes of worship which prevailed in the Roman world were all considered by the people as equally true; by the philosopher as equally false; and by the magistrate as equally useful."

— Edward Gibbon, The History of the Decline and Fall of the Roman Empire, vol. I, ch. II. (here) (It's worth reading it in context.)



(It is frequently attributed, in the form you gave, to Seneca the Younger, and also Lucretius. There appears to be some mystery as to the correct attribution of the shorter version, assuming it is sourcable.)