Yogananda: Finding the joy in Life
Material objects which give joy remain outside of the mind; they only gain entry into the mind through imagination. Joy, from its very nature, is something born of the mind and lives closest in it. External, material objects can be destroyed, but this joy within can never be destroyed if one knows how to keep it and unless the possessor of joy changes his mind and becomes sorrowful. This joy is ever-new and indestructible.