14 But the Ninevites, although a barbarous and foreign people who had never participated in any of these benefits, small or great, neither words, nor wonders, nor works, when they saw a man who had been saved from shipwreck, who had never associated with them before, but appeared then for the first time, enter their city and say “yet three days and Nineveh shall be overthrown,” were so converted and reformed by the mere sound of these words, and putting away their former wickedness, advanced in the direction of virtue by the path of repentance, that they caused the sentence of God to be revoked, and arrested the threatened disturbance of their city, and averted the heaven-sent wrath, and were delivered from every kind of evil.
“For,” we read, “God saw that every man turned from his evil way, and was converted to the Lord.” How turned? I ask. Although their wickedness was great, their iniquity unspeakable, their moral sores difficult to heal, which was plainly shown by the prophet when he said “their wickedness ascended even unto the heaven:” indicating by the distance of the place the magnitude of their wickedness; nevertheless such great iniquity which was piled up to such a height as to reach even to the heaven, all this in the course of three days in a brief moment of time through the effect of a few words which they heard from the mouth of one man and he an unknown shipwrecked stranger they so thoroughly abolished, removed out of sight, and put away, as to have the happiness of hearing the declaration “God saw that every one turned from his evil way, and He repented of the evil which God said He would do them.”
Do you see that he who is temperate and watchful not only suffers no injury at the hands of man, but even turns back Heaven-sent wrath? Whereas he who betrays himself and harms himself by his own doing, even if he receives countess benefits, reaps no great advantage. So, at least, the Jews were not profited by those great miracles, nor on the other hand were the Ninevites harmed by having no share in them; but inasmuch as they were inwardly well-disposed, having laid hold of a slight opportunity they became better, barbarians and foreigners though they were, ignorant of all divine revelation, and dwelling at a distance from Palestine.
Source: No One Can Harm the Man Who Does Not Injure Himself (New Advent)