The reward of suffering is experience.

God

And even in our sleep pain that cannot forget falls drop by drop upon the heart, and in our own despair, against our will, comes wisdom to us by the awful grace of God.

Learning

It is always in season for old men to learn.

Power

The man whose authority is recent is always stern.

Tyranny

In every tyrant's heart there springs in the end this poison, that he cannot trust a friend.