The times that most profoundly affects the course of a person's soul are the times he struggles with and battling his persecutors and oppressors to uphold and strengthen his faith... Such an experience, though fraught with pain of the body and agony of the soul, is rich with powerful impressions. These are the days of light in the life of man.
Rabbi Yosef Yitzchak of Lubavitch (1880-1950), writing about his imprisonment by the Soviets in 1927