John Chrysostom

For God even preferred that His own prediction should fall to the ground, so that the city should not fall. Or rather, the prophecy did not even so fall to the ground. For if indeed while the men continued in the same wickedness, the sentence had not taken effect, some one perhaps might have brought a charge against what was uttered. But if when they had changed, and desisted from their iniquity, God also desisted from His wrath, who shall be able any longer to find fault with the prophecy, or to convict the things spoken of falsehood. The same law indeed which God had laid down from the beginning, publishing it to all men by the prophet, was on that occasion strictly observed. What then is this law? "I shall speak a sentence," saith He, "concerning a nation or a kingdom, to pluck up, and to pull down, and to destroy it; and it shall be, that if they repent of their evil, I will also repent of the wrath which I said I would do unto them." Guarding then this law, he saved those who were converted and released from His wrath those who desisted from their wickedness.

Let us imitate the spiritual wisdom of the barbarians. They repented even on uncertain grounds! For the sentence had no such clause, "If ye turn and repent, I will set up the city;" but simply, "Yet three days, and Nineveh shall be overthrown." What then said they? "Who knoweth whether God will repent of the evil He said He would do unto us?" Who knoweth? They know not the end of the event, and yet they do not neglect repentance! They are unacquainted with God's method of shewing mercy, and yet they change upon the strength of uncertainties! For neither was it in their power to look at other Ninevites who had repented and been saved; nor had they read prophets; nor had they heard patriarchs; nor had they enjoyed counsel, or partaken of admonition; nor had they persuaded themselves that they should certainly propitiate God by repentance. For the threatening did not imply this: but they were doubtful, and hesitating concerning it; and yet they repented with all diligence. What reason then shall we have to urge, when those, who had no ground for confidence as to the issue, are seen to have exhibited so great a change; but thou who hast ground of confidence in the mercy of God, and who hast frequently received many pledges of His care, and hast heard prophets, and apostles, and hast been instructed by actual events; hast yet no emulation to reach the same measure of virtue as these did! Great assuredly was their virtue! but greater by far was the mercy of God!… For that fear was the cause of its safety. The threatening effected the deliverance from the peril. The sentence of overthrow put a stop to the overthrow. O strange and astonishing event! the sentence threatening death, brought forth life!… Was Nineveh overthrown? Was the city destroyed? Nay, quite the contrary; it both arose, and became still more distinguished; and long as is the time which has elapsed, it has not effaced its glory, but we all still celebrate and admire it even to this day. For from that time it hath been a sort of excellent haven for all who have sinned, not suffering them to sink into desperation, but calling all to repentance; and by what it did, and by what it obtained of God's favour, persuading men never to despair of their salvation.