“Fortunate the man who, at the right moment meets the right friend; fortunate also the man who at the right moment meets the right enemy. I do not approve the extermination of the enemy; the policy of exterminating or, as it is barbarously said, liquidating enemies, is one of the most alarming developments of modern war and peace, from the point of view of those who desire the survival of culture. One needs the enemy… A country within which the divisions have goon too far is a danger to itself: a country which is too well united - whether by nature or by device, by hounest purpose or by fraud and oppression - is a menace to others.”

For My Legionaries: The Iron Guard (1936), Jewish Problem

As quoted in "Considerations By the Way" in Conduct of Life by Ralph Waldo Emerson
Variant translation: Believe me, a thousand friends suffice thee not; In a single enemy thou hast more than enough

Source: Eifelheim (2006), Chapter XIV (p. 252)

Speech at the Executive Club of Chicago, December 19, 1941

1960s, Special message to Congress on the right to vote (1965)
Context: In our system, the first right and most vital of all our fights is the right to vote. Jefferson described the elective franchise as "the ark of our safety." It is from the exercise of this right that the guarantee of all our other rights flows. Unless the right to vote be secure and undenied, all other rights are insecure and subject to denial for all our citizens. The challenge to this right is a challenge to America itself. We must meet this challenge as decisively as we would meet a challenge mounted against our land from enemies abroad.

Moralia: Sayings of Kings and Commanders, Plutarch; English translation by Frank Cole Babbitt
Variant translation by Goodwin:
He that is afraid of scoffs and reproaches is more a coward than he that flies from the enemy.

Quoted in "The Civilizing Mission: A History of the Italo-Ethiopian War of 1935-1936" - Page 172 - by A. J. Barker - 1968