Oftentimes great and open temptations are the most harmless because they come with banners flying and bands playing and all the munitions of war in full view, so that we know we are in the midst of enemies that mean us damage, and we get ready to meet and resist them. Our peculiar dangers are those that surprise us and work treachery in our fort.

Metaphors, Similes and Other Characteristic Sayings of Henry Ward Beecher (ed. 1895)