This is an awesome quote that is often misattributed to Thucydides but actually from Sir William Francis Butler's, "Charles George Gordon" (1889), p. 85

https://en.wikiquote.org/wiki/Thucydides and https://books.google.com/books?id=i6dCAAAAYAAJ&pg=PA85&dq=cowards+fools+inauthor:William+inauthor:Francis+inauthor:Butler&hl=en&sa=X&ei=UQjKULnhMc200QHQ1oD4Bw#v=onepage&q=cowards%20fools%20inauthor%3AWilliam%20inauthor%3AFrancis%20inauthor%3AButler&f=false