One must not think, however, that every instance of suffering endured on this world is necessarily the indication of a specific wrong. They are often simply trials chosen by a spirit to  finish its purification and  to  accelerate its advancement. Hence, expiation  always serves as a trial, but a trial is not always an expiation. Trials or expiations, however, are always signs of a relatively low order spirit, because one who is perfect has no more need of being tested. Consequently, a spirit may have acquired a certain degree of elevation, but wanting to advance further, it requests a mission, a task to complete. The more trying the struggle, the more it will be recompensed if it emerges victorious. Such are, more specifically, those persons of naturally good instincts, of elevated spirit and noble innate sentiments, who seem to  have brought nothing evil from their previous existence, and who endure the greatest afflictions with wholly Christian resignation, asking God that they might bear them without complaining. On the other hand, one may consider as expiations those afflictions that provoke complaint and compel humans to rebel against God.

Suffering that does not provoke complaint may undoubtedly be an  expiation, but  this indicates it  was voluntarily chosen beforehand rather than  imposed, and it  is a test of a strong resolution, which is a sign of progress.