Aristotle:

Anybody can become angry, that is easy; but to be angry with the right person, and to the right degree, and at the right time, and for the right purpose, and in the right way, that is not within everybody's power, that is not easy.

Carl Sandburg:

Choose
The single clenched fist lifted and ready,
Or the open hand held out and waiting.
Choose:
For we meet by one or the other.

D. H. Lawrence:

The only justice is to follow the sincere intuition of the soul, angry or gentle. Anger is just, and pity is just, but judgement is never just.

Elizabeth Kenny:

He who angers you conquers you.

Elizabeth Kenny:

My mother used to say, "He who angers you, conquers you!" But my mother was a saint.

Emily Dickinson:

Anger as soon as fed is dead --

'tis starving makes it fat.

Epictetus :

Reckon the days in which you have not been angry. I used to be angry every day; now every other day; then every third and fourth day; and if you miss it so long as thirty days, offer a sacrifice of thanksgiving to God.

Eric Hoffer:

The remarkable thing is that we really love our neighbor as ourselves: we do unto others as we do unto ourselves. We hate others when we hate ourselves. We are tolerant toward others when we tolerate ourselves. We forgive others when we forgive ourselves. We are prone to sacrifice others when we are ready to sacrifice ourselves.

Frederick Buechner:

Of the Seven Deadly Sins, anger is possibly the most fun. To lick your wounds, to smack your lips over grievances long past, to roll over your tongue the prospect of bitter confrontations still to come, to savor to the last toothsome morsel both the pain you are given and the pain you are giving back -- in many ways it is a feast fit for a king. The chief drawback is that what you are wolfing down is yourself. The skeleton at the feast is you.

James Thurber:

Let us not look back in anger or forward in fear, but around in awareness.

John Dryden:

The intoxication of anger, like that of the grape, shows us to others, but hides us from ourselves.

Louisa May Alcott:

I am angry nearly every day of my life, but I have learned not to show it; and I still try to hope not to feel it, though it may take me another forty years to do it. [Character of Marmee in Little Women]

Marcus Aurelius:

How much more grievous are the consequences of anger than the causes of it.

Thomas a Kempis:

Be not angry that you cannot make others as you wish them to be, since you cannot make yourself as you wish to be.

William Arthur Ward:

Flying off the handle sometimes causes hammers and humans to lose their heads, as well as their effectiveness.

William Blake:

I was angry with my friend
I told my wrath, my wrath did end.
I was angry with my foe:
I told it not, my wrath did grow.

A Poison Tree