9 Moreover, if the Christian know and keep fast under what condition and what law he has believed, he will be aware that he must suffer more than others in the world, since he must struggle more with the attacks of the devil. Holy Scripture teaches and forewarns, saying, “My son, when you come to the service of God, stand in righteousness and fear, and prepare your soul for temptation.” And again: “In pain endure, and in your humility have patience; for gold and silver is tried in the fire, but acceptable men in the furnace of humiliation.”
Source: The Treatises of Cyprian (New Advent)