From Kahlil Gibran's The Prophet

And a woman spoke, saying, Tell us of Pain.

And he said:

Your pain is the breaking of the shell
that encloses your understanding.

Even as the stone of the fruit must break, that its
heart may stand in the sun, so must you know pain.

And could you keep your heart in wonder
at the daily miracles of your life, your pain
would not seem less wondrous than your joy;

And you would accept the seasons of your
heart, even as you have always accepted
the seasons that pass over your fields.

And you would watch with serenity
through the winters of your grief.

Much of your pain is self-chosen.

It is the bitter potion by which the
physician within you heals your sick self.

Therefore trust the physician, and drink
his remedy in silence and tranquillity:

For his hand, though heavy and hard, is guided
by the tender hand of the Unseen,
And the cup he brings, though it burn your lips,
has been fashioned of the clay which the Potter
has moistened with His own sacred tears.