Allan Kardec. The book of spirits (№ 397449)

You chose the test. The more difficult the better you survive, the more you are exalted. Those who spend their lives in affluence and human happiness, the essence of cowardly spirits, frozen in its development. Thus, the accidents in this world far exceeds the number of happy, because spirits are mostly looking for tests that would be more fruitful for them. They see all too well the emptiness of your honors and pleasures. However, life is indeed the happiest always in motion, always in tension, and not simply the absence of pain.