History of the Peloponnesian War

But with regard to barbarians, of whom you are now afraid through inexperience, you ought to know, both from the contest you have already had with those of them who are Macedonians, and from what I myself conjecture, and indeed have ascertained from hearsay, that they will not prove formidable.

For with regard to such points in an enemy as have an appearance of strength, while they are in reality weak, when correct information is gained respecting them, it rather gives confidence to those who resist them: whereas in the case of those who have any solid advantage, men would meet them the more boldly from having no previous acquaintance with them.