Seeing them, therefore, so beaten and so badly used, I was grieved for them, because they were so tormented, and had no rest at all. And I said to the Shepherd who talked with me, “Sir, who is this shepherd, who is so pitiless and severe, and so completely devoid of compassion for these sheep?” “This,” he replied, “is the angel of punishment; and he belongs to the just angels, and is appointed to punish. He accordingly takes those who wander away from God, and who have walked in the desires and deceits of this world, and chastises them as they deserve with terrible and diverse punishments.”
“I would know, sir,” I said, “Of what nature are these diverse tortures and punishments?” “Hear,” he said, “the various tortures and punishments. The tortures are such as occur during life. For some are punished with losses, others with want, others with sicknesses of various kinds, and others with all kinds of disorder and confusion; others are insulted by unworthy persons, and exposed to suffering in many other ways: for many, becoming unstable in their plans, try many things, and none of them at all succeed, and they say they are not prosperous in their undertakings; and it does not occur to their minds that they have done evil deeds, but they blame the Lord. When, therefore, they have been afflicted with all kinds of affliction, then are they delivered unto me for good training, and they are made strong in the faith of the Lord; and for the rest of the days of their life they are subject to the Lord with pure hearts, and are successful in all their undertakings, obtaining from the Lord everything they ask; and then they glorify the Lord, that they were delivered to me, and no longer suffer any evil.”
Source: The Pastor (or "The Shepherd") (New Advent)