Laudator Temporis Acti

Gore Vidal (1925-2012), Julian (1964; rpt. New York: Modern Library, 1984), p. 142:

The malice of a true Christian attempting to destroy an opponent is something unique in the world. No other religion ever considered it necessary to destroy others because they did not share the same beliefs. At worst, another man's belief might inspire amusement or contempt—the Egyptians and their animal gods, for instance. Yet those who worshipped the Bull did not try to murder those who worshipped the Snake, or to convert them by force from Snake to Bull. No evil ever entered the world quite so vividly or on such a vast scale as Christianity did.

But cf. Juvenal's 15th satire, on the religious feud between inhabitants of two Egyptian villages, lines 33-38 (tr. Susanna Morton Braund):

Between the neighbours Ombi and Tentyra there still blazes a lasting and ancient feud, an undying hatred, a wound that can never be healed. On each side, the height of mob fury arises because each place detests the gods of their neighbours. They think that only the gods they themselves worship should be counted as gods.

inter finitimos vetus atque antiqua simultas,
inmortale odium et numquam sanabile vulnus,
ardet adhuc Ombos et Tentura. summus utrimque
inde furor volgo, quod numina vicinorum
odit uterque locus, cum solos credat habendos
esse deos quos ipse colit.