Suppose they gave a war and nobody came?
Why, then the war would come to you.

He who stays home when the fight begins
And lets others fight for his cause
should take care:
He who does not take part in the battle
will share in the defeat.
Even avoiding battle
does not avoid battle,
since not to fight for your own cause really means
Fighting on behalf of your enemy's cause.

lines 3ff.: B. Brecht