It is very foolish to attack one’s enemy openly if one can injure him in secret.

—Giambattista Giraldi, 1543

Put national causes first and personal grudges last.

—Sima Qian, c. 91 BC

Quarrels would not last long if the fault was only on one side.

—La Rochefoucauld, 1665

Today’s friend may be tomorrow’s foe.

—Sophocles, 440 BC

It would seem that in history it’s never a tooth for a tooth, but a thousand, a hundred thousand for one.

—Sybille Bedford, 1963

One of the most time-consuming things is to have an enemy.

—E.B. White, 1977

To outwit an enemy is not only just and glorious but profitable and sweet.

—Plutarch, c. 100

The hatred of relatives is the bitterest.

—Tacitus, 117

An injury is much sooner forgotten than an insult.

—Philip Dormer Stanhope, 1746

The envious die not once, but as often as the envied win applause.

—Baltasar Gracián, 1647

Enemies to me are the sauce piquant to my dish of life.

—Elsa Maxwell, 1955

Don’t hit a man at all if you can avoid it, but if you have to hit him, knock him out.

—Theodore Roosevelt, 1916

I tell you, there is such a thing as creative hate!

—Willa Cather, 1915