From the moment that a man begins to look less to his changeful outer possessions and more to his controllable internal ones, he begins to gain the chance for real happiness. When this truth breaks upon the intelligence, he learns to keep his final reserves hidden in his heart. Then whatever happens, whatever course fortune takes, no one and nothing can take it from him. So long as he can carry the knowledge of truth in his head and the peace of God in his heart, he can carry the best of all his possessions with him wherever he may go. Not having lodged his possessions--whether material things or human affections, capitalized wealth or social honours--in his heart but having kept them outside it where they belong, he can remain calm and unmoved when Fortune's caprice disturbs or even destroys them. He has learnt to keep within his heart only inalienable possessions like wisdom and virtue, only what renders him serenely independent of her revolutions.
He who depends on externals plays dice with his happiness. He who depends on his own Overself attains unfailing serenity.
-- Notebooks Category 24: The Peace within You > Chapter 3: Practise Detachment > # 279