Solitary trees, if they grow at all, grow strong.
Winston Churchill

Character is higher than intellect. A great soul will be strong
to live as well as think. Ralph Waldo Emerson

 The world breaks everyone, and afterward, some are strong at
the broken places.
Ernest Hemingway

He who conquers others is strong; He who conquers himself is
mighty.
Lao Tzu

In the world there is nothing more submissive and weak than
water. Yet for attacking that which is hard and strong nothing can surpass
it.
Lao Tzu

It is funny that men who are supposed to be scientific cannot
get themselves to realise the basic principle of physics, that action and
reaction are equal and opposite, that when you persecute people you always rouse
them to be strong and stronger.
Gertrude Stein

And when a woman's will is as strong as the man's who wants to
govern her, half her strength must be concealment. George Eliot

I shall argue that strong men, conversely, know when to
compromise and that all principles can be compromised to serve a greater
principle.
Andrew Carnegie

When you do the wrong thing, knowing it is wrong, you do so
because you haven't developed the habit of effectively controlling or
neutralizing strong inner urges that tempt you, or because you have established
the wrong habit and don't know how to eliminate them effectively.
W.
Clement Stone

The world breaks everyone, and afterward, some are strong at
the broken places.
Ernest Hemingway